v19.5.0-rc.2

Prepare changelog for v19.5.0-rc.2
Fix release.sh
2022-09-06 12:21:02 +01:00 · 2022-09-06 12:21:01 +01:00 · 2022-09-06 12:20:41 +01:00 · 2022-09-06 12:18:10 +01:00 · 2022-09-06 12:17:40 +01:00 · 2022-09-06 12:11:27 +01:00
99 changed files with 11310 additions and 5886 deletions
@@ -9,6 +9,8 @@ module.exports = {
        browser: true,
        node: true,
    },
+    // NOTE: These rules are frozen and new rules should not be added here.
+    // New changes belong in https://github.com/matrix-org/eslint-plugin-matrix-org/
    rules: {
        "no-var": ["warn"],
        "prefer-rest-params": ["warn"],
@@ -55,6 +57,10 @@ module.exports = {
            // We're okay with assertion errors when we ask for them
            "@typescript-eslint/no-non-null-assertion": "off",

+            // The non-TypeScript rule produces false positives
+            "func-call-spacing": "off",
+            "@typescript-eslint/func-call-spacing": ["error"],
+
            "quotes": "off",
            // We use a `logger` intermediary module
            "no-console": "error",
@@ -0,0 +1,6 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "github>matrix-org/renovate-config-element-web"
+  ]
+}
@@ -0,0 +1,30 @@
+name: Backport
+on:
+  pull_request_target:
+    types:
+      - closed
+      - labeled
+    branches:
+      - develop
+
+jobs:
+  backport:
+    name: Backport
+    runs-on: ubuntu-latest
+    # Only react to merged PRs for security reasons.
+    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
+    if: >
+      github.event.pull_request.merged
+      && (
+        github.event.action == 'closed'
+        || (
+          github.event.action == 'labeled'
+          && contains(github.event.label.name, 'backport')
+        )
+      )
+    steps:
+      - uses: tibdex/backport@v2
+        with:
+          labels_template: "<%= JSON.stringify(labels) %>"
+          # We can't use GITHUB_TOKEN here or CI won't run on the new PR
+          github_token: ${{ secrets.ELEMENT_BOT_TOKEN }}
@@ -20,7 +20,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Notify matrix-react-sdk repo that a new SDK build is on develop so it can CI against it
-        uses: peter-evans/repository-dispatch@v1
+        uses: peter-evans/repository-dispatch@v2
        with:
          token: ${{ secrets.ELEMENT_BOT_TOKEN }}
          repository: ${{ matrix.repo }}
@@ -30,7 +30,7 @@ jobs:
      pull-requests: read
    steps:
      - name: Add notice
-        uses: actions/github-script@v5
+        uses: actions/github-script@v6
        if: contains(github.event.pull_request.labels.*.name, 'X-Blocked')
        with:
          script: |
@@ -52,7 +52,7 @@ jobs:

      - name: Add label
        if: ${{ steps.teams.outputs.isTeamMember == 'false' }}
-        uses: actions/github-script@v5
+        uses: actions/github-script@v6
        with:
          script: |
            github.rest.issues.addLabels({
@@ -71,7 +71,7 @@ jobs:
      github.event.pull_request.head.repo.full_name != github.repository
    steps:
      - name: Close pull request
-        uses: actions/github-script@v5
+        uses: actions/github-script@v6
        with:
          script: |
            github.rest.issues.createComment({
@@ -0,0 +1,40 @@
+# Must only be called from `release#published` triggers
+name: Publish to npm
+on:
+  workflow_call:
+    secrets:
+      NPM_TOKEN:
+        required: true
+concurrency: ${{ github.workflow }}-${{ github.ref }}
+jobs:
+  npm:
+    name: Publish to npm
+    runs-on: ubuntu-latest
+    steps:
+      - name: 🧮 Checkout code
+        uses: actions/checkout@v3
+
+      - name: 🔧 Yarn cache
+        uses: actions/setup-node@v3
+        with:
+          cache: "yarn"
+
+      - name: 🔨 Install dependencies
+        run: "yarn install --pure-lockfile"
+
+      - name: 🚀 Publish to npm
+        id: npm-publish
+        uses: JS-DevTools/npm-publish@v1
+        with:
+          token: ${{ secrets.NPM_TOKEN }}
+          access: public
+          tag: next
+
+      - name: 🎖️ Add `latest` dist-tag to final releases
+        if: github.event.release.prerelease == false
+        run: |
+          package=$(cat package.json | jq -er .name)
+          npm dist-tag add "$package@$release" latest
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+          release: ${{ steps.npm-publish.outputs.version }}
@@ -24,7 +24,6 @@ jobs:

      - name: 📋 Copy to temp
        run: |
-          ls -lah
          tag="${{ github.ref_name }}"
          version="${tag#v}"
          echo "VERSION=$version" >> $GITHUB_ENV
@@ -40,7 +39,7 @@ jobs:
          cp -a "$RUNNER_TEMP/$VERSION" .

          # Add the new directory to the index if it isn't there already
-          if ! grep -q "Version $VERSION" index.html; then
+          if ! grep -q ">Version $VERSION</a>" index.html; then
            perl -i -pe 'BEGIN {$rel=shift} $_ =~ /^<\/ul>/ && print
              "<li><a href=\"${rel}/index.html\">Version ${rel}</a></li>\n"' "$VERSION" index.html
          fi
@@ -51,3 +50,9 @@ jobs:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          keep_files: true
          publish_dir: .
+
+  npm:
+    name: Publish
+    uses: matrix-org/matrix-js-sdk/.github/workflows/release-npm.yml@develop
+    secrets:
+      NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
@@ -11,7 +11,7 @@ jobs:
    name: "Typescript Syntax Check"
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3

      - uses: actions/setup-node@v3
        with:
@@ -27,7 +27,7 @@ jobs:
    name: "ESLint"
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3

      - uses: actions/setup-node@v3
        with:
@@ -43,7 +43,7 @@ jobs:
    name: "JSDoc Checker"
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3

      - uses: actions/setup-node@v3
        with:
@@ -54,3 +54,38 @@ jobs:

      - name: Generate Docs
        run: "yarn run gendoc"
+
+  tsc-strict:
+    name: Typescript Strict Error Checker
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: read
+      checks: write
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Get diff lines
+        id: diff
+        uses: Equip-Collaboration/diff-line-numbers@v1.0.0
+        with:
+          include: '["\\.tsx?$"]'
+
+      - name: Detecting files changed
+        id: files
+        uses: futuratrepadeira/changed-files@v3.2.1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          pattern: '^.*\.tsx?$'
+
+      - uses: t3chguy/typescript-check-action@main
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          use-check: false
+          check-fail-mode: added
+          output-behaviour: annotate
+          ts-extra-args: '--strict'
+          files-changed: ${{ steps.files.outputs.files_updated }}
+          files-added: ${{ steps.files.outputs.files_created }}
+          files-deleted: ${{ steps.files.outputs.files_deleted }}
+          line-numbers: ${{ steps.diff.outputs.lineNumbers }}
@@ -12,7 +12,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3

      - name: Yarn cache
        uses: actions/setup-node@v3
@@ -29,7 +29,7 @@ jobs:
        run: "yarn coverage --ci --reporters github-actions"

      - name: Upload Artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
        with:
          name: coverage
          path: |
@@ -1,3 +1,71 @@
+Changes in [19.5.0-rc.2](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.5.0-rc.2) (2022-09-06)
+============================================================================================================
+
+Changes in [19.5.0-rc.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.5.0-rc.1) (2022-09-06)
+============================================================================================================
+
+## 🐛 Bug Fixes
+ * Fix bug in deepCompare which would incorrectly return objects with disjoint keys as equal ([\#2586](https://github.com/matrix-org/matrix-js-sdk/pull/2586)). Contributed by @3nprob.
+ * Refactor Sync and fix `initialSyncLimit` ([\#2587](https://github.com/matrix-org/matrix-js-sdk/pull/2587)).
+ * Use deep equality comparisons when searching for outgoing key requests by target ([\#2623](https://github.com/matrix-org/matrix-js-sdk/pull/2623)). Contributed by @duxovni.
+ * Fix room membership race with PREPARED event ([\#2613](https://github.com/matrix-org/matrix-js-sdk/pull/2613)). Contributed by @jotto.
+
+Changes in [19.4.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.4.0) (2022-08-31)
+==================================================================================================
+
+## 🔒 Security
+* Fix for [CVE-2022-36059](https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE%2D2022%2D36059)
+
+Find more details at https://matrix.org/blog/2022/08/31/security-releases-matrix-js-sdk-19-4-0-and-matrix-react-sdk-3-53-0
+
+## ✨ Features
+ * Re-emit room state events on rooms ([\#2607](https://github.com/matrix-org/matrix-js-sdk/pull/2607)).
+ * Add ability to override built in room name generator for an i18n'able one ([\#2609](https://github.com/matrix-org/matrix-js-sdk/pull/2609)).
+ * Add txn_id support to sliding sync ([\#2567](https://github.com/matrix-org/matrix-js-sdk/pull/2567)).
+
+## 🐛 Bug Fixes
+ * Refactor Sync and fix `initialSyncLimit` ([\#2587](https://github.com/matrix-org/matrix-js-sdk/pull/2587)).
+ * Use deep equality comparisons when searching for outgoing key requests by target ([\#2623](https://github.com/matrix-org/matrix-js-sdk/pull/2623)). Contributed by @duxovni.
+ * Fix room membership race with PREPARED event ([\#2613](https://github.com/matrix-org/matrix-js-sdk/pull/2613)). Contributed by @jotto.
+ * fixed a sliding sync bug which could cause the `roomIndexToRoomId` map to be incorrect when a new room is added in the middle of the list or when an existing room is deleted from the middle of the list. ([\#2610](https://github.com/matrix-org/matrix-js-sdk/pull/2610)).
+ * Fix: Handle parsing of a beacon info event without asset ([\#2591](https://github.com/matrix-org/matrix-js-sdk/pull/2591)). Fixes vector-im/element-web#23078. Contributed by @kerryarchibald.
+ * Fix finding event read up to if stable private read receipts is missing ([\#2585](https://github.com/matrix-org/matrix-js-sdk/pull/2585)). Fixes vector-im/element-web#23027.
+ * fixed a sliding sync issue where history could be interpreted as live events. ([\#2583](https://github.com/matrix-org/matrix-js-sdk/pull/2583)).
+
+Changes in [19.3.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.3.0) (2022-08-16)
+==================================================================================================
+
+## ✨ Features
+ * Add txn_id support to sliding sync ([\#2567](https://github.com/matrix-org/matrix-js-sdk/pull/2567)).
+ * Emit an event when the client receives TURN servers ([\#2529](https://github.com/matrix-org/matrix-js-sdk/pull/2529)).
+ * Add support for stable prefixes for MSC2285 ([\#2524](https://github.com/matrix-org/matrix-js-sdk/pull/2524)).
+ * Remove stream-replacement ([\#2551](https://github.com/matrix-org/matrix-js-sdk/pull/2551)).
+ * Add support for sending user-defined encrypted to-device messages ([\#2528](https://github.com/matrix-org/matrix-js-sdk/pull/2528)).
+ * Retry to-device messages ([\#2549](https://github.com/matrix-org/matrix-js-sdk/pull/2549)). Fixes vector-im/element-web#12851.
+ * Sliding sync: add missing filters from latest MSC ([\#2555](https://github.com/matrix-org/matrix-js-sdk/pull/2555)).
+ * Use stable prefixes for MSC3827 ([\#2537](https://github.com/matrix-org/matrix-js-sdk/pull/2537)).
+
+## 🐛 Bug Fixes
+ * Fix: Handle parsing of a beacon info event without asset ([\#2591](https://github.com/matrix-org/matrix-js-sdk/pull/2591)). Fixes vector-im/element-web#23078.
+ * Fix finding event read up to if stable private read receipts is missing ([\#2585](https://github.com/matrix-org/matrix-js-sdk/pull/2585)). Fixes vector-im/element-web#23027.
+ * Fixed a sliding sync issue where history could be interpreted as live events. ([\#2583](https://github.com/matrix-org/matrix-js-sdk/pull/2583)).
+ * Don't load the sync accumulator if there's already a sync persist in flight ([\#2569](https://github.com/matrix-org/matrix-js-sdk/pull/2569)).
+
+Changes in [19.2.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.2.0) (2022-08-02)
+==================================================================================================
+
+## 🦖 Deprecations
+ * Remove unstable support for `m.room_key.withheld` ([\#2512](https://github.com/matrix-org/matrix-js-sdk/pull/2512)). Fixes #2233.
+
+## ✨ Features
+ * Sliding sync: add missing filters from latest MSC ([\#2555](https://github.com/matrix-org/matrix-js-sdk/pull/2555)).
+ * Use stable prefixes for MSC3827 ([\#2537](https://github.com/matrix-org/matrix-js-sdk/pull/2537)).
+ * Add support for MSC3575: Sliding Sync ([\#2242](https://github.com/matrix-org/matrix-js-sdk/pull/2242)).
+
+## 🐛 Bug Fixes
+ * Correct the units in TURN servers expiry documentation ([\#2520](https://github.com/matrix-org/matrix-js-sdk/pull/2520)).
+ * Re-insert room IDs when decrypting bundled redaction events returned by `/sync` ([\#2531](https://github.com/matrix-org/matrix-js-sdk/pull/2531)). Contributed by @duxovni.
+
 Changes in [19.1.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.1.0) (2022-07-26)
 ==================================================================================================

@@ -1,284 +1,5 @@
 Contributing code to matrix-js-sdk
 ==================================

-Everyone is welcome to contribute code to matrix-js-sdk, provided that they are
-willing to license their contributions under the same license as the project
-itself. We follow a simple 'inbound=outbound' model for contributions: the act
-of submitting an 'inbound' contribution means that the contributor agrees to
-license the code under the same terms as the project's overall 'outbound'
-license - in this case, Apache Software License v2 (see
-[LICENSE](LICENSE)).
+matrix-js-sdk follows the same pattern as https://github.com/vector-im/element-web/blob/develop/CONTRIBUTING.md

-How to contribute
-----------------
-
-The preferred and easiest way to contribute changes to the project is to fork
-it on github, and then create a pull request to ask us to pull your changes
-into our repo (https://help.github.com/articles/using-pull-requests/)
-
-We use GitHub's pull request workflow to review the contribution, and either
-ask you to make any refinements needed or merge it and make them ourselves.
-
-Things that should go into your PR description:
- * A changelog entry in the `Notes` section (see below)
- * References to any bugs fixed by the change (in GitHub's `Fixes` notation)
- * Describe the why and what is changing in the PR description so it's easy for
-   onlookers and reviewers to onboard and context switch. This information is
-   also helpful when we come back to look at this in 6 months and ask "why did
-   we do it like that?" we have a chance of finding out.
-      * Why didn't it work before? Why does it work now? What use cases does it
-        unlock?
-      * If you find yourself adding information on how the code works or why you
-        chose to do it the way you did, make sure this information is instead
-        written as comments in the code itself.
-      * Sometimes a PR can change considerably as it is developed. In this case,
-        the description should be updated to reflect the most recent state of
-        the PR. (It can be helpful to retain the old content under a suitable
-        heading, for additional context.)
- * Include both **before** and **after** screenshots to easily compare and discuss
-   what's changing.
- * Include a step-by-step testing strategy so that a reviewer can check out the
-   code locally and easily get to the point of testing your change.
- * Add comments to the diff for the reviewer that might help them to understand
-   why the change is necessary or how they might better understand and review it.
-
-We rely on information in pull request to populate the information that goes
-into the changelogs our users see, both for the JS SDK itself and also for some
-projects based on it. This is picked up from both labels on the pull request and
-the `Notes:` annotation in the description. By default, the PR title will be
-used for the changelog entry, but you can specify more options, as follows.
-
-To add a longer, more detailed description of the change for the changelog:
-
-
-*Fix llama herding bug*
-
-```
-Notes: Fix a bug (https://github.com/matrix-org/notaproject/issues/123) where the 'Herd' button would not herd more than 8 Llamas if the moon was in the waxing gibbous phase
-```
-
-For some PRs, it's not useful to have an entry in the user-facing changelog (this is
-the default for PRs labelled with `T-Task`):
-
-*Remove outdated comment from `Ungulates.ts`*
-```
-Notes: none
-```
-
-Sometimes, you're fixing a bug in a downstream project, in which case you want
-an entry in that project's changelog. You can do that too:
-
-*Fix another herding bug*
-```
-Notes: Fix a bug where the `herd()` function would only work on Tuesdays
-element-web notes: Fix a bug where the 'Herd' button only worked on Tuesdays
-```
-
-This example is for Element Web. You can specify:
- * matrix-react-sdk
- * element-web
- * element-desktop
-
-If your PR introduces a breaking change, use the `Notes` section in the same
-way, additionally adding the `X-Breaking-Change` label (see below). There's no need
-to specify in the notes that it's a breaking change - this will be added
-automatically based on the label - but remember to tell the developer how to
-migrate:
-
-*Remove legacy class*
-
-```
-Notes: Remove legacy `Camelopard` class. `Giraffe` should be used instead.
-```
-
-Other metadata can be added using labels.
- * `X-Breaking-Change`: A breaking change - adding this label will mean the change causes a *major* version bump.
- * `T-Enhancement`: A new feature - adding this label will mean the change causes a *minor* version bump.
- * `T-Defect`: A bug fix (in either code or docs).
- * `T-Task`: No user-facing changes, eg. code comments, CI fixes, refactors or tests. Won't have a changelog entry unless you specify one.
-
-If you don't have permission to add labels, your PR reviewer(s) can work with you
-to add them: ask in the PR description or comments.
-
-We use continuous integration, and all pull requests get automatically tested:
-if your change breaks the build, then the PR will show that there are failed
-checks, so please check back after a few minutes.
-
-Tests
-----
-Your PR should include tests.
-
-For new user facing features in `matrix-react-sdk` or `element-web`, you
-must include:
-
-1. Comprehensive unit tests written in Jest. These are located in `/test`.
-2. "happy path" end-to-end tests.
-   These are located in `/test/end-to-end-tests` in `matrix-react-sdk`, and
-   are run using `element-web`. Ideally, you would also include tests for edge
-   and error cases.
-
-Unit tests are expected even when the feature is in labs. It's good practice
-to write tests alongside the code as it ensures the code is testable from
-the start, and gives you a fast feedback loop while you're developing the
-functionality. End-to-end tests should be added prior to the feature
-leaving labs, but don't have to be present from the start (although it might
-be beneficial to have some running early, so you can test things faster).
-
-For bugs in those repos, your change must include at least one unit test or
-end-to-end test; which is best depends on what sort of test most concisely
-exercises the area.
-
-Changes to `matrix-js-sdk` must be accompanied by unit tests written in Jest.
-These are located in `/spec/`.
-
-When writing unit tests, please aim for a high level of test coverage
-for new code - 80% or greater. If you cannot achieve that, please document
-why it's not possible in your PR.
-
-Some sections of code are not sensible to add coverage for, such as those
-which explicitly inhibit noisy logging for tests. Which can be hidden using
-an istanbul magic comment as [documented here][1]. See example:
-```javascript
-/* istanbul ignore if */
-if (process.env.NODE_ENV !== "test") {
-    logger.error("Log line that is noisy enough in tests to want to skip");
-}
-```
-
-Tests validate that your change works as intended and also document
-concisely what is being changed. Ideally, your new tests fail
-prior to your change, and succeed once it has been applied. You may
-find this simpler to achieve if you write the tests first.
-
-If you're spiking some code that's experimental and not being used to support
-production features, exceptions can be made to requirements for tests.
-Note that tests will still be required in order to ship the feature, and it's
-strongly encouraged to think about tests early in the process, as adding
-tests later will become progressively more difficult.
-
-If you're not sure how to approach writing tests for your change, ask for help
-in [#element-dev](https://matrix.to/#/#element-dev:matrix.org).
-
-Code style
----------
-The js-sdk aims to target TypeScript/ES6. All new files should be written in
-TypeScript and existing files should use ES6 principles where possible.
-
-Members should not be exported as a default export in general - it causes problems
-with the architecture of the SDK (index file becomes less clear) and could
-introduce naming problems (as default exports get aliased upon import). In
-general, avoid using `export default`.
-
-The remaining code-style for matrix-js-sdk is not formally documented, but
-contributors are encouraged to read the
-[code style document for matrix-react-sdk](https://github.com/matrix-org/matrix-react-sdk/blob/master/code_style.md)
-and follow the principles set out there.
-
-Please ensure your changes match the cosmetic style of the existing project,
-and ***never*** mix cosmetic and functional changes in the same commit, as it
-makes it horribly hard to review otherwise.
-
-Attribution
-----------
-Everyone who contributes anything to Matrix is welcome to be listed in the
-AUTHORS.rst file for the project in question. Please feel free to include a
-change to AUTHORS.rst in your pull request to list yourself and a short
-description of the area(s) you've worked on. Also, we sometimes have swag to
-give away to contributors - if you feel that Matrix-branded apparel is missing
-from your life, please mail us your shipping address to matrix at matrix.org
-and we'll try to fix it :)
-
-Sign off
--------
-In order to have a concrete record that your contribution is intentional
-and you agree to license it under the same terms as the project's license, we've
-adopted the same lightweight approach that the Linux Kernel
-(https://www.kernel.org/doc/Documentation/SubmittingPatches), Docker
-(https://github.com/docker/docker/blob/master/CONTRIBUTING.md), and many other
-projects use: the DCO (Developer Certificate of Origin:
-http://developercertificate.org/). This is a simple declaration that you wrote
-the contribution or otherwise have the right to contribute it to Matrix:
-
-```
-Developer Certificate of Origin
-Version 1.1
-
-Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
-660 York Street, Suite 102,
-San Francisco, CA 94110 USA
-
-Everyone is permitted to copy and distribute verbatim copies of this
-license document, but changing it is not allowed.
-
-Developer's Certificate of Origin 1.1
-
-By making a contribution to this project, I certify that:
-
-(a) The contribution was created in whole or in part by me and I
-    have the right to submit it under the open source license
-    indicated in the file; or
-
-(b) The contribution is based upon previous work that, to the best
-    of my knowledge, is covered under an appropriate open source
-    license and I have the right under that license to submit that
-    work with modifications, whether created in whole or in part
-    by me, under the same open source license (unless I am
-    permitted to submit under a different license), as indicated
-    in the file; or
-
-(c) The contribution was provided directly to me by some other
-    person who certified (a), (b) or (c) and I have not modified
-    it.
-
-(d) I understand and agree that this project and the contribution
-    are public and that a record of the contribution (including all
-    personal information I submit with it, including my sign-off) is
-    maintained indefinitely and may be redistributed consistent with
-    this project or the open source license(s) involved.
-```
-
-If you agree to this for your contribution, then all that's needed is to
-include the line in your commit or pull request comment:
-
-```
-Signed-off-by: Your Name <your@email.example.org>
-```
-
-We accept contributions under a legally identifiable name, such as your name on
-government documentation or common-law names (names claimed by legitimate usage
-or repute). Unfortunately, we cannot accept anonymous contributions at this
-time.
-
-Git allows you to add this signoff automatically when using the `-s` flag to
-`git commit`, which uses the name and email set in your `user.name` and
-`user.email` git configs.
-
-If you forgot to sign off your commits before making your pull request and are
-on Git 2.17+ you can mass signoff using rebase:
-
-```
-git rebase --signoff origin/develop
-```
-
-Review expectations
-===================
-
-See https://github.com/vector-im/element-meta/wiki/Review-process
-
-
-Merge Strategy
-==============
-
-The preferred method for merging pull requests is squash merging to keep the
-commit history trim, but it is up to the discretion of the team member merging
-the change. We do not support rebase merges due to `allchange` being unable to
-handle them. When merging make sure to leave the default commit title, or 
-at least leave the PR number at the end in brackets like by default.
-When stacking pull requests, you may wish to do the following:
-
-1. Branch from develop to your branch (branch1), push commits onto it and open a pull request
-2. Branch from your base branch (branch1) to your work branch (branch2), push commits and open a pull request configuring the base to be branch1, saying in the description that it is based on your other PR.
-3. Merge the first PR using a merge commit otherwise your stacked PR will need a rebase. Github will automatically adjust the base branch of your other PR to be develop.
-
-
-[1]: https://github.com/gotwarlost/istanbul/blob/master/ignoring-code-for-coverage.md
@@ -1,6 +1,6 @@
 {
  "name": "matrix-js-sdk",
-  "version": "19.1.0",
+  "version": "19.5.0-rc.2",
  "description": "Matrix Client-Server SDK for Javascript",
  "engines": {
    "node": ">=12.9.0"
@@ -56,11 +56,11 @@
    "@babel/runtime": "^7.12.5",
    "another-json": "^0.2.0",
    "browser-request": "^0.3.3",
-    "bs58": "^4.0.1",
+    "bs58": "^5.0.0",
    "content-type": "^1.0.4",
    "loglevel": "^1.7.1",
    "matrix-events-sdk": "^0.0.1-beta.7",
-    "p-retry": "^4.5.0",
+    "p-retry": "4",
    "qs": "^6.9.6",
    "request": "^2.88.2",
    "unhomoglyph": "^1.0.6"
@@ -78,11 +78,11 @@
    "@babel/preset-env": "^7.12.11",
    "@babel/preset-typescript": "^7.12.7",
    "@babel/register": "^7.12.10",
-    "@matrix-org/olm": "https://gitlab.matrix.org/api/v4/projects/27/packages/npm/@matrix-org/olm/-/@matrix-org/olm-3.2.8.tgz",
+    "@matrix-org/olm": "https://gitlab.matrix.org/api/v4/projects/27/packages/npm/@matrix-org/olm/-/@matrix-org/olm-3.2.12.tgz",
    "@types/bs58": "^4.0.1",
    "@types/content-type": "^1.1.5",
    "@types/jest": "^28.0.0",
-    "@types/node": "12",
+    "@types/node": "16",
    "@types/request": "^2.48.5",
    "@typescript-eslint/eslint-plugin": "^5.6.0",
    "@typescript-eslint/parser": "^5.6.0",
@@ -92,17 +92,17 @@
    "better-docs": "^2.4.0-beta.9",
    "browserify": "^17.0.0",
    "docdash": "^1.2.0",
-    "eslint": "8.18.0",
+    "eslint": "8.22.0",
    "eslint-config-google": "^0.14.0",
    "eslint-plugin-import": "^2.25.4",
-    "eslint-plugin-matrix-org": "^0.5.0",
-    "exorcist": "^1.0.1",
-    "fake-indexeddb": "^3.1.2",
+    "eslint-plugin-matrix-org": "^0.6.0",
+    "exorcist": "^2.0.0",
+    "fake-indexeddb": "^4.0.0",
    "jest": "^28.0.0",
    "jest-localstorage-mock": "^2.4.6",
    "jest-sonar-reporter": "^2.0.0",
    "jsdoc": "^3.6.6",
-    "matrix-mock-request": "^2.0.1",
+    "matrix-mock-request": "^2.1.2",
    "rimraf": "^3.0.2",
    "terser": "^5.5.1",
    "tsify": "^5.0.2",
@@ -0,0 +1,37 @@
+#!/bin/bash
+#
+# Script to perform a post-release steps of matrix-js-sdk.
+#
+# Requires:
+#   jq; install from your distribution's package manager (https://stedolan.github.io/jq/)
+
+set -e
+
+jq --version > /dev/null || (echo "jq is required: please install it"; kill $$)
+
+if [ "$(git branch -lr | grep origin/develop -c)" -ge 1 ]; then
+    # When merging to develop, we need revert the `main` and `typings` fields if we adjusted them previously.
+    for i in main typings
+    do
+        # If a `lib` prefixed value is present, it means we adjusted the field
+        # earlier at publish time, so we should revert it now.
+        if [ "$(jq -r ".matrix_lib_$i" package.json)" != "null" ]; then
+            # If there's a `src` prefixed value, use that, otherwise delete.
+            # This is used to delete the `typings` field and reset `main` back
+            # to the TypeScript source.
+            src_value=$(jq -r ".matrix_src_$i" package.json)
+            if [ "$src_value" != "null" ]; then
+                jq ".$i = .matrix_src_$i" package.json > package.json.new && mv package.json.new package.json
+            else
+                jq "del(.$i)" package.json > package.json.new && mv package.json.new package.json
+            fi
+        fi
+    done
+
+    if [ -n "$(git ls-files --modified package.json)" ]; then
+        echo "Committing develop package.json"
+        git commit package.json -m "Resetting package fields for development"
+    fi
+
+    git push origin develop
+fi
@@ -3,19 +3,16 @@
 # Script to perform a release of matrix-js-sdk and downstream projects.
 #
 # Requires:
-#   github-changelog-generator; install via:
-#     pip install git+https://github.com/matrix-org/github-changelog-generator.git
 #   jq; install from your distribution's package manager (https://stedolan.github.io/jq/)
 #   hub; install via brew (macOS) or source/pre-compiled binaries (debian) (https://github.com/github/hub) - Tested on v2.2.9
-#   npm; typically installed by Node.js
 #   yarn; install via brew (macOS) or similar (https://yarnpkg.com/docs/install/)
 #
-# Note: this script is also used to release matrix-react-sdk and element-web.
+# Note: this script is also used to release matrix-react-sdk, element-web, and element-desktop.

 set -e

 jq --version > /dev/null || (echo "jq is required: please install it"; kill $$)
-if [[ `command -v hub` ]] && [[ `hub --version` =~ hub[[:space:]]version[[:space:]]([0-9]*).([0-9]*) ]]; then
+if [[ $(command -v hub) ]] && [[ $(hub --version) =~ hub[[:space:]]version[[:space:]]([0-9]*).([0-9]*) ]]; then
    HUB_VERSION_MAJOR=${BASH_REMATCH[1]}
    HUB_VERSION_MINOR=${BASH_REMATCH[2]}
    if [[ $HUB_VERSION_MAJOR -lt 2 ]] || [[ $HUB_VERSION_MAJOR -eq 2 && $HUB_VERSION_MINOR -lt 5 ]]; then
@@ -26,7 +23,6 @@ else
    echo "hub is required: please install it"
    exit
 fi
-npm --version > /dev/null || (echo "npm is required: please install it"; kill $$)
 yarn --version > /dev/null || (echo "yarn is required: please install it"; kill $$)

 USAGE="$0 [-x] [-c changelog_file] vX.Y.Z"
@@ -37,7 +33,6 @@ $USAGE

    -c changelog_file:  specify name of file containing changelog
    -x:                 skip updating the changelog
-    -n:                 skip publish to NPM
 EOF
 }

@@ -59,10 +54,8 @@ if ! git diff-files --quiet; then
 fi

 skip_changelog=
-skip_npm=
 changelog_file="CHANGELOG.md"
-expected_npm_user="matrixdotorg"
-while getopts hc:u:xzn f; do
+while getopts hc:x f; do
    case $f in
        h)
            help
@@ -74,21 +67,58 @@ while getopts hc:u:xzn f; do
        x)
            skip_changelog=1
            ;;
-        n)
-            skip_npm=1
-            ;;
-        u)
-            expected_npm_user="$OPTARG"
-            ;;
    esac
 done
-shift `expr $OPTIND - 1`
+shift $(expr $OPTIND - 1)

 if [ $# -ne 1 ]; then
    echo "Usage: $USAGE" >&2
    exit 1
 fi

+function check_dependency {
+    echo "Checking version of $1..."
+    local depver=$(cat package.json | jq -r .dependencies[\"$1\"])
+    local latestver=$(yarn info -s "$1" dist-tags.next)
+    if [ "$depver" != "$latestver" ]
+    then
+        echo "The latest version of $1 is $latestver but package.json depends on $depver."
+        echo -n "Type 'u' to auto-upgrade, 'c' to continue anyway, or 'a' to abort:"
+        read resp
+        if [ "$resp" != "u" ] && [ "$resp" != "c" ]
+        then
+            echo "Aborting."
+            exit 1
+        fi
+        if [ "$resp" == "u" ]
+        then
+            echo "Upgrading $1 to $latestver..."
+            yarn add -E "$1@$latestver"
+            git add -u
+            git commit -m "Upgrade $1 to $latestver"
+        fi
+    fi
+}
+
+function reset_dependency {
+    echo "Resetting $1 to develop branch..."
+    yarn add "github:matrix-org/$1#develop"
+    git add -u
+    git commit -m "Reset $1 back to develop branch"
+}
+
+has_subprojects=0
+if [ -f release_config.yaml ]; then
+    subprojects=$(cat release_config.yaml | python -c "import yaml; import sys; print(' '.join(list(yaml.load(sys.stdin)['subprojects'].keys())))" 2> /dev/null)
+    if [ "$?" -eq 0 ]; then
+        has_subprojects=1
+        echo "Checking subprojects for upgrades"
+        for proj in $subprojects; do
+            check_dependency "$proj"
+        done
+    fi
+fi
+
 # We use Git branch / commit dependencies for some packages, and Yarn seems
 # to have a hard time getting that right. See also
 # https://github.com/yarnpkg/yarn/issues/4734. As a workaround, we clean the
@@ -97,16 +127,6 @@ yarn cache clean
 # Ensure all dependencies are updated
 yarn install --ignore-scripts --pure-lockfile

-# Login and publish continues to use `npm`, as it seems to have more clearly
-# defined options and semantics than `yarn` for writing to the registry.
-if [ -z "$skip_npm" ]; then
-    actual_npm_user=`npm whoami`;
-    if [ $expected_npm_user != $actual_npm_user ]; then
-        echo "you need to be logged into npm as $expected_npm_user, but you are logged in as $actual_npm_user" >&2
-        exit 1
-    fi
-fi
-
 # ignore leading v on release
 release="${1#v}"
 tag="v${release}"
@@ -117,18 +137,20 @@ prerelease=0
 # see if the version has a hyphen in it. Crude,
 # but semver doesn't support postreleases so anything
 # with a hyphen is a prerelease.
-echo $release | grep -q '-' && prerelease=1
+echo "$release" | grep -q '-' && prerelease=1

 if [ $prerelease -eq 1 ]; then
    echo Making a PRE-RELEASE
+else
+    read -p "Making a FINAL RELEASE, press enter to continue " REPLY
 fi

-# we might already be on the release branch, in which case, yay
-# If we're on any branch starting with 'release', we don't create
-# a separate release branch (this allows us to use the same
+# We might already be on the release branch, in which case, yay
+# If we're on any branch starting with 'release', or the staging branch
+# we don't create a separate release branch (this allows us to use the same
 # release branch for releases and release candidates).
 curbranch=$(git symbolic-ref --short HEAD)
-if [[ "$curbranch" != release* ]]; then
+if [[ "$curbranch" != release* && "$curbranch" != "staging" ]]; then
    echo "Creating release branch"
    git checkout -b "$rel_branch"
 else
@@ -141,13 +163,13 @@ if [ -z "$skip_changelog" ]; then
    yarn run allchange "$release"
    read -p "Edit $changelog_file manually, or press enter to continue " REPLY

-    if [ -n "$(git ls-files --modified $changelog_file)" ]; then
+    if [ -n "$(git ls-files --modified "$changelog_file")" ]; then
        echo "Committing updated changelog"
        git commit "$changelog_file" -m "Prepare changelog for $tag"
    fi
 fi
-latest_changes=`mktemp`
-cat "${changelog_file}" | `dirname $0`/scripts/changelog_head.py > "${latest_changes}"
+latest_changes=$(mktemp)
+cat "${changelog_file}" | "$(dirname "$0")/scripts/changelog_head.py" > "${latest_changes}"

 set -x

@@ -174,7 +196,7 @@ do
 done

 # commit yarn.lock if it exists, is versioned, and is modified
-if [[ -f yarn.lock && `git status --porcelain yarn.lock | grep '^ M'` ]];
+if [[ -f yarn.lock && $(git status --porcelain yarn.lock | grep '^ M') ]];
 then
    pkglock='yarn.lock'
 else
@@ -186,7 +208,7 @@ git commit package.json $pkglock -m "$tag"
 # figure out if we should be signing this release
 signing_id=
 if [ -f release_config.yaml ]; then
-    result=`cat release_config.yaml | python -c "import yaml; import sys; print yaml.load(sys.stdin)['signing_id']" 2> /dev/null || true`
+    result=$(cat release_config.yaml | python -c "import yaml; import sys; print(yaml.load(sys.stdin)['signing_id'])" 2> /dev/null || true)
    if [ "$?" -eq 0 ]; then
        signing_id=$result
    fi
@@ -204,8 +226,8 @@ assets=''
 dodist=0
 jq -e .scripts.dist package.json 2> /dev/null || dodist=$?
 if [ $dodist -eq 0 ]; then
-    projdir=`pwd`
-    builddir=`mktemp -d 2>/dev/null || mktemp -d -t 'mytmpdir'`
+    projdir=$(pwd)
+    builddir=$(mktemp -d 2>/dev/null || mktemp -d -t 'mytmpdir')
    echo "Building distribution copy in $builddir"
    pushd "$builddir"
    git clone "$projdir" .
@@ -230,7 +252,7 @@ fi
 if [ -n "$signing_id" ]; then
    # make a signed tag
    # gnupg seems to fail to get the right tty device unless we set it here
-    GIT_COMMITTER_EMAIL="$signing_id" GPG_TTY=`tty` git tag -u "$signing_id" -F "${latest_changes}" "$tag"
+    GIT_COMMITTER_EMAIL="$signing_id" GPG_TTY=$(tty) git tag -u "$signing_id" -F "${latest_changes}" "$tag"
 else
    git tag -a -F "${latest_changes}" "$tag"
 fi
@@ -268,7 +290,7 @@ if [ -n "$signing_id" ]; then
    curl -L "${gh_project_url}/archive/${tarfile}" -o "${tarfile}"

    # unzip it and compare it with the tar we would generate
-    if ! cmp --silent <(gunzip -c $tarfile) \
+    if ! cmp --silent <(gunzip -c "$tarfile") \
         <(git archive --format tar --prefix="${project_name}-${release}/" "$tag"); then

        # we don't bail out here, because really it's more likely that our comparison
@@ -296,11 +318,11 @@ if [ $prerelease -eq 1 ]; then
    hubflags='-p'
 fi

-release_text=`mktemp`
+release_text=$(mktemp)
 echo "$tag" > "${release_text}"
 echo >> "${release_text}"
 cat "${latest_changes}" >> "${release_text}"
-hub release create $hubflags $assets -F "${release_text}" "$tag"
+hub release create $hubflags "$assets" -F "${release_text}" "$tag"

 if [ $dodist -eq 0 ]; then
    rm -rf "$builddir"
@@ -308,19 +330,6 @@ fi
 rm "${release_text}"
 rm "${latest_changes}"

-# Login and publish continues to use `npm`, as it seems to have more clearly
-# defined options and semantics than `yarn` for writing to the registry.
-# Tag both releases and prereleases as `next` so the last stable release remains
-# the default.
-if [ -z "$skip_npm" ]; then
-    npm publish --tag next
-    if [ $prerelease -eq 0 ]; then
-        # For a release, also add the default `latest` tag.
-        package=$(cat package.json | jq -er .name)
-        npm dist-tag add "$package@$release" latest
-    fi
-fi
-
 # if it is a pre-release, leave it on the release branch for now.
 if [ $prerelease -eq 1 ]; then
    git checkout "$rel_branch"
@@ -337,34 +346,19 @@ git merge "$rel_branch" --no-edit
 git push origin master

 # finally, merge master back onto develop (if it exists)
-if [ $(git branch -lr | grep origin/develop -c) -ge 1 ]; then
+if [ "$(git branch -lr | grep origin/develop -c)" -ge 1 ]; then
    git checkout develop
    git pull
    git merge master --no-edit
-
-    # When merging to develop, we need revert the `main` and `typings` fields if
-    # we adjusted them previously.
-    for i in main typings
-    do
-        # If a `lib` prefixed value is present, it means we adjusted the field
-        # earlier at publish time, so we should revert it now.
-        if [ "$(jq -r ".matrix_lib_$i" package.json)" != "null" ]; then
-            # If there's a `src` prefixed value, use that, otherwise delete.
-            # This is used to delete the `typings` field and reset `main` back
-            # to the TypeScript source.
-            src_value=$(jq -r ".matrix_src_$i" package.json)
-            if [ "$src_value" != "null" ]; then
-                jq ".$i = .matrix_src_$i" package.json > package.json.new && mv package.json.new package.json
-            else
-                jq "del(.$i)" package.json > package.json.new && mv package.json.new package.json
-            fi
-        fi
-    done
-
-    if [ -n "$(git ls-files --modified package.json)" ]; then
-        echo "Committing develop package.json"
-        git commit package.json -m "Resetting package fields for development"
-    fi
-
+    git push origin develop
+fi
+
+[ -x ./post-release.sh ] && ./post-release.sh
+
+if [ $has_subprojects -eq 1 ] && [ $prerelease -eq 0 ]; then
+    echo "Resetting subprojects to develop"
+    for proj in $subprojects; do
+        reset_dependency "$proj"
+    done
    git push origin develop
 fi
@@ -1,16 +0,0 @@
-{
-    "extends": [
-        "config:base",
-        ":dependencyDashboardApproval"
-    ],
-    "labels": ["T-Task", "Dependencies"],
-    "lockFileMaintenance": { "enabled": true },
-    "groupName": "all",
-    "packageRules": [{
-        "matchFiles": ["package.json"],
-        "rangeStrategy": "update-lockfile"
-    }],
-    "platformAutomerge": true,
-    "automerge": true,
-    "automergeType": "pr"
-}
@@ -1,6 +1,6 @@
 /*
 Copyright 2015, 2016 OpenMarket Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -17,31 +17,32 @@ limitations under the License.

 /**
 * A mock implementation of the webstorage api
- * @constructor
 */
-export function MockStorageApi() {
-    this.data = {};
-    this.keys = [];
-    this.length = 0;
-}
+export class MockStorageApi {
+    public data: Record<string, string> = {};
+    public keys: string[] = [];
+    public length = 0;

-MockStorageApi.prototype = {
-    setItem: function(k, v) {
+    public setItem(k: string, v: string): void {
        this.data[k] = v;
-        this._recalc();
-    },
-    getItem: function(k) {
+        this.recalc();
+    }
+
+    public getItem(k: string): string | null {
        return this.data[k] || null;
-    },
-    removeItem: function(k) {
+    }
+
+    public removeItem(k: string): void {
        delete this.data[k];
-        this._recalc();
-    },
-    key: function(index) {
+        this.recalc();
+    }
+
+    public key(index: number): string {
        return this.keys[index];
-    },
-    _recalc: function() {
-        const keys = [];
+    }
+
+    private recalc(): void {
+        const keys: string[] = [];
        for (const k in this.data) {
            if (!this.data.hasOwnProperty(k)) {
                continue;
@@ -50,6 +51,5 @@ MockStorageApi.prototype = {
        }
        this.keys = keys;
        this.length = keys.length;
-    },
-};
-
+    }
+}
@@ -39,8 +39,8 @@ import { IKeysUploadResponse, IUploadKeysRequest } from '../src/client';
 export class TestClient {
    public readonly httpBackend: MockHttpBackend;
    public readonly client: MatrixClient;
-    private deviceKeys: IDeviceKeys;
-    private oneTimeKeys: Record<string, IOneTimeKey>;
+    public deviceKeys: IDeviceKeys;
+    public oneTimeKeys: Record<string, IOneTimeKey>;

    constructor(
        public readonly userId?: string,
@@ -50,7 +50,7 @@ export class TestClient {
        options?: Partial<ICreateClientOpts>,
    ) {
        if (sessionStoreBackend === undefined) {
-            sessionStoreBackend = new MockStorageApi();
+            sessionStoreBackend = new MockStorageApi() as unknown as Storage;
        }

        this.httpBackend = new MockHttpBackend();
@@ -1,758 +0,0 @@
-/*
-Copyright 2016 OpenMarket Ltd
-Copyright 2017 Vector Creations Ltd
-Copyright 2018 New Vector Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-/* This file consists of a set of integration tests which try to simulate
- * communication via an Olm-encrypted room between two users, Alice and Bob.
- *
- * Note that megolm (group) conversation is not tested here.
- *
- * See also `megolm.spec.js`.
- */
-
-// load olm before the sdk if possible
-import '../olm-loader';
-
-import { logger } from '../../src/logger';
-import * as testUtils from "../test-utils/test-utils";
-import { TestClient } from "../TestClient";
-import { CRYPTO_ENABLED } from "../../src/client";
-
-let aliTestClient;
-const roomId = "!room:localhost";
-const aliUserId = "@ali:localhost";
-const aliDeviceId = "zxcvb";
-const aliAccessToken = "aseukfgwef";
-let bobTestClient;
-const bobUserId = "@bob:localhost";
-const bobDeviceId = "bvcxz";
-const bobAccessToken = "fewgfkuesa";
-let aliMessages;
-let bobMessages;
-
-function bobUploadsDeviceKeys() {
-    bobTestClient.expectDeviceKeyUpload();
-    return Promise.all([
-        bobTestClient.client.uploadKeys(),
-        bobTestClient.httpBackend.flush(),
-    ]).then(() => {
-        expect(Object.keys(bobTestClient.deviceKeys).length).not.toEqual(0);
-    });
-}
-
-/**
- * Set an expectation that ali will query bobs keys; then flush the http request.
- *
- * @return {promise} resolves once the http request has completed.
- */
-function expectAliQueryKeys() {
-    // can't query keys before bob has uploaded them
-    expect(bobTestClient.deviceKeys).toBeTruthy();
-
-    const bobKeys = {};
-    bobKeys[bobDeviceId] = bobTestClient.deviceKeys;
-    aliTestClient.httpBackend.when("POST", "/keys/query")
-            .respond(200, function(path, content) {
-        expect(content.device_keys[bobUserId]).toEqual(
-            [],
-            "Expected Alice to key query for " + bobUserId + ", got " +
-            Object.keys(content.device_keys),
-        );
-        const result = {};
-        result[bobUserId] = bobKeys;
-        return { device_keys: result };
-    });
-    return aliTestClient.httpBackend.flush("/keys/query", 1);
-}
-
-/**
- * Set an expectation that bob will query alis keys; then flush the http request.
- *
- * @return {promise} which resolves once the http request has completed.
- */
-function expectBobQueryKeys() {
-    // can't query keys before ali has uploaded them
-    expect(aliTestClient.deviceKeys).toBeTruthy();
-
-    const aliKeys = {};
-    aliKeys[aliDeviceId] = aliTestClient.deviceKeys;
-    logger.log("query result will be", aliKeys);
-
-    bobTestClient.httpBackend.when(
-        "POST", "/keys/query",
-    ).respond(200, function(path, content) {
-        expect(content.device_keys[aliUserId]).toEqual(
-            [],
-            "Expected Bob to key query for " + aliUserId + ", got " +
-            Object.keys(content.device_keys),
-        );
-        const result = {};
-        result[aliUserId] = aliKeys;
-        return { device_keys: result };
-    });
-    return bobTestClient.httpBackend.flush("/keys/query", 1);
-}
-
-/**
- * Set an expectation that ali will claim one of bob's keys; then flush the http request.
- *
- * @return {promise} resolves once the http request has completed.
- */
-function expectAliClaimKeys() {
-    return bobTestClient.awaitOneTimeKeyUpload().then((keys) => {
-        aliTestClient.httpBackend.when(
-            "POST", "/keys/claim",
-        ).respond(200, function(path, content) {
-            const claimType = content.one_time_keys[bobUserId][bobDeviceId];
-            expect(claimType).toEqual("signed_curve25519");
-            let keyId = null;
-            for (keyId in keys) {
-                if (bobTestClient.oneTimeKeys.hasOwnProperty(keyId)) {
-                    if (keyId.indexOf(claimType + ":") === 0) {
-                        break;
-                    }
-                }
-            }
-            const result = {};
-            result[bobUserId] = {};
-            result[bobUserId][bobDeviceId] = {};
-            result[bobUserId][bobDeviceId][keyId] = keys[keyId];
-            return { one_time_keys: result };
-        });
-    }).then(() => {
-        // it can take a while to process the key query, so give it some extra
-        // time, and make sure the claim actually happens rather than ploughing on
-        // confusingly.
-        return aliTestClient.httpBackend.flush("/keys/claim", 1, 500).then((r) => {
-            expect(r).toEqual(1, "Ali did not claim Bob's keys");
-        });
-    });
-}
-
-function aliDownloadsKeys() {
-    // can't query keys before bob has uploaded them
-    expect(bobTestClient.getSigningKey()).toBeTruthy();
-
-    const p1 = aliTestClient.client.downloadKeys([bobUserId]).then(function() {
-        return aliTestClient.client.getStoredDevicesForUser(bobUserId);
-    }).then((devices) => {
-        expect(devices.length).toEqual(1);
-        expect(devices[0].deviceId).toEqual("bvcxz");
-    });
-    const p2 = expectAliQueryKeys();
-
-    // check that the localStorage is updated as we expect (not sure this is
-    // an integration test, but meh)
-    return Promise.all([p1, p2]).then(() => {
-        return aliTestClient.client.crypto.deviceList.saveIfDirty();
-    }).then(() => {
-        aliTestClient.client.cryptoStore.getEndToEndDeviceData(null, (data) => {
-            const devices = data.devices[bobUserId];
-            expect(devices[bobDeviceId].keys).toEqual(bobTestClient.deviceKeys.keys);
-            expect(devices[bobDeviceId].verified).
-                toBe(0); // DeviceVerification.UNVERIFIED
-        });
-    });
-}
-
-function aliEnablesEncryption() {
-    return aliTestClient.client.setRoomEncryption(roomId, {
-        algorithm: "m.olm.v1.curve25519-aes-sha2",
-    }).then(function() {
-        expect(aliTestClient.client.isRoomEncrypted(roomId)).toBeTruthy();
-    });
-}
-
-function bobEnablesEncryption() {
-    return bobTestClient.client.setRoomEncryption(roomId, {
-        algorithm: "m.olm.v1.curve25519-aes-sha2",
-    }).then(function() {
-       expect(bobTestClient.client.isRoomEncrypted(roomId)).toBeTruthy();
-    });
-}
-
-/**
- * Ali sends a message, first claiming e2e keys. Set the expectations and
- * check the results.
- *
- * @return {promise} which resolves to the ciphertext for Bob's device.
- */
-function aliSendsFirstMessage() {
-    return Promise.all([
-        sendMessage(aliTestClient.client),
-        expectAliQueryKeys()
-            .then(expectAliClaimKeys)
-            .then(expectAliSendMessageRequest),
-    ]).then(function([_, ciphertext]) {
-        return ciphertext;
-    });
-}
-
-/**
- * Ali sends a message without first claiming e2e keys. Set the expectations
- * and check the results.
- *
- * @return {promise} which resolves to the ciphertext for Bob's device.
- */
-function aliSendsMessage() {
-    return Promise.all([
-        sendMessage(aliTestClient.client),
-        expectAliSendMessageRequest(),
-    ]).then(function([_, ciphertext]) {
-        return ciphertext;
-    });
-}
-
-/**
- * Bob sends a message, first querying (but not claiming) e2e keys. Set the
- * expectations and check the results.
- *
- * @return {promise} which resolves to the ciphertext for Ali's device.
- */
-function bobSendsReplyMessage() {
-    return Promise.all([
-        sendMessage(bobTestClient.client),
-        expectBobQueryKeys()
-            .then(expectBobSendMessageRequest),
-    ]).then(function([_, ciphertext]) {
-        return ciphertext;
-    });
-}
-
-/**
- * Set an expectation that Ali will send a message, and flush the request
- *
- * @return {promise} which resolves to the ciphertext for Bob's device.
- */
-function expectAliSendMessageRequest() {
-    return expectSendMessageRequest(aliTestClient.httpBackend).then(function(content) {
-        aliMessages.push(content);
-        expect(Object.keys(content.ciphertext)).toEqual([bobTestClient.getDeviceKey()]);
-        const ciphertext = content.ciphertext[bobTestClient.getDeviceKey()];
-        expect(ciphertext).toBeTruthy();
-        return ciphertext;
-    });
-}
-
-/**
- * Set an expectation that Bob will send a message, and flush the request
- *
- * @return {promise} which resolves to the ciphertext for Bob's device.
- */
-function expectBobSendMessageRequest() {
-    return expectSendMessageRequest(bobTestClient.httpBackend).then(function(content) {
-        bobMessages.push(content);
-        const aliKeyId = "curve25519:" + aliDeviceId;
-        const aliDeviceCurve25519Key = aliTestClient.deviceKeys.keys[aliKeyId];
-        expect(Object.keys(content.ciphertext)).toEqual([aliDeviceCurve25519Key]);
-        const ciphertext = content.ciphertext[aliDeviceCurve25519Key];
-        expect(ciphertext).toBeTruthy();
-        return ciphertext;
-    });
-}
-
-function sendMessage(client) {
-    return client.sendMessage(
-        roomId, { msgtype: "m.text", body: "Hello, World" },
-    );
-}
-
-function expectSendMessageRequest(httpBackend) {
-    const path = "/send/m.room.encrypted/";
-    const prom = new Promise((resolve) => {
-        httpBackend.when("PUT", path).respond(200, function(path, content) {
-            resolve(content);
-            return {
-                event_id: "asdfgh",
-            };
-        });
-    });
-
-    // it can take a while to process the key query
-    return httpBackend.flush(path, 1).then(() => prom);
-}
-
-function aliRecvMessage() {
-    const message = bobMessages.shift();
-    return recvMessage(
-        aliTestClient.httpBackend, aliTestClient.client, bobUserId, message,
-    );
-}
-
-function bobRecvMessage() {
-    const message = aliMessages.shift();
-    return recvMessage(
-        bobTestClient.httpBackend, bobTestClient.client, aliUserId, message,
-    );
-}
-
-function recvMessage(httpBackend, client, sender, message) {
-    const syncData = {
-        next_batch: "x",
-        rooms: {
-            join: {
-
-            },
-        },
-    };
-    syncData.rooms.join[roomId] = {
-        timeline: {
-            events: [
-                testUtils.mkEvent({
-                    type: "m.room.encrypted",
-                    room: roomId,
-                    content: message,
-                    sender: sender,
-                }),
-            ],
-        },
-    };
-    httpBackend.when("GET", "/sync").respond(200, syncData);
-
-    const eventPromise = new Promise((resolve, reject) => {
-        const onEvent = function(event) {
-            // ignore the m.room.member events
-            if (event.getType() == "m.room.member") {
-                return;
-            }
-            logger.log(client.credentials.userId + " received event",
-                        event);
-
-            client.removeListener("event", onEvent);
-            resolve(event);
-        };
-        client.on("event", onEvent);
-    });
-
-    httpBackend.flush();
-
-    return eventPromise.then((event) => {
-        expect(event.isEncrypted()).toBeTruthy();
-
-        // it may still be being decrypted
-        return testUtils.awaitDecryption(event);
-    }).then((event) => {
-        expect(event.getType()).toEqual("m.room.message");
-        expect(event.getContent()).toMatchObject({
-            msgtype: "m.text",
-            body: "Hello, World",
-        });
-        expect(event.isEncrypted()).toBeTruthy();
-    });
-}
-
-/**
- * Send an initial sync response to the client (which just includes the member
- * list for our test room).
- *
- * @param {TestClient} testClient
- * @returns {Promise} which resolves when the sync has been flushed.
- */
-function firstSync(testClient) {
-    // send a sync response including our test room.
-    const syncData = {
-        next_batch: "x",
-        rooms: {
-            join: { },
-        },
-    };
-    syncData.rooms.join[roomId] = {
-        state: {
-            events: [
-                testUtils.mkMembership({
-                    mship: "join",
-                    user: aliUserId,
-                }),
-                testUtils.mkMembership({
-                    mship: "join",
-                    user: bobUserId,
-                }),
-            ],
-        },
-        timeline: {
-            events: [],
-        },
-    };
-
-    testClient.httpBackend.when("GET", "/sync").respond(200, syncData);
-    return testClient.flushSync();
-}
-
-describe("MatrixClient crypto", function() {
-    if (!CRYPTO_ENABLED) {
-        return;
-    }
-
-    beforeEach(async function() {
-        aliTestClient = new TestClient(aliUserId, aliDeviceId, aliAccessToken);
-        await aliTestClient.client.initCrypto();
-
-        bobTestClient = new TestClient(bobUserId, bobDeviceId, bobAccessToken);
-        await bobTestClient.client.initCrypto();
-
-        aliMessages = [];
-        bobMessages = [];
-    });
-
-    afterEach(function() {
-        aliTestClient.httpBackend.verifyNoOutstandingExpectation();
-        bobTestClient.httpBackend.verifyNoOutstandingExpectation();
-
-        return Promise.all([aliTestClient.stop(), bobTestClient.stop()]);
-    });
-
-    it("Bob uploads device keys", function() {
-        return Promise.resolve()
-            .then(bobUploadsDeviceKeys);
-    });
-
-    it("Ali downloads Bobs device keys", function() {
-        return Promise.resolve()
-            .then(bobUploadsDeviceKeys)
-            .then(aliDownloadsKeys);
-    });
-
-    it("Ali gets keys with an invalid signature", function() {
-        return Promise.resolve()
-            .then(bobUploadsDeviceKeys)
-            .then(function() {
-                // tamper bob's keys
-                const bobDeviceKeys = bobTestClient.deviceKeys;
-                expect(bobDeviceKeys.keys["curve25519:" + bobDeviceId]).toBeTruthy();
-                bobDeviceKeys.keys["curve25519:" + bobDeviceId] += "abc";
-
-                return Promise.all([
-                    aliTestClient.client.downloadKeys([bobUserId]),
-                    expectAliQueryKeys(),
-                ]);
-            }).then(function() {
-                return aliTestClient.client.getStoredDevicesForUser(bobUserId);
-            }).then((devices) => {
-                // should get an empty list
-                expect(devices).toEqual([]);
-            });
-    });
-
-    it("Ali gets keys with an incorrect userId", function() {
-        const eveUserId = "@eve:localhost";
-
-        const bobDeviceKeys = {
-            algorithms: ['m.olm.v1.curve25519-aes-sha2', 'm.megolm.v1.aes-sha2'],
-            device_id: 'bvcxz',
-            keys: {
-                'ed25519:bvcxz': 'pYuWKMCVuaDLRTM/eWuB8OlXEb61gZhfLVJ+Y54tl0Q',
-                'curve25519:bvcxz': '7Gni0loo/nzF0nFp9847RbhElGewzwUXHPrljjBGPTQ',
-            },
-            user_id: '@eve:localhost',
-            signatures: {
-                '@eve:localhost': {
-                    'ed25519:bvcxz': 'CliUPZ7dyVPBxvhSA1d+X+LYa5b2AYdjcTwG' +
-                        '0stXcIxjaJNemQqtdgwKDtBFl3pN2I13SEijRDCf1A8bYiQMDg',
-                },
-            },
-        };
-
-        const bobKeys = {};
-        bobKeys[bobDeviceId] = bobDeviceKeys;
-        aliTestClient.httpBackend.when(
-            "POST", "/keys/query",
-        ).respond(200, function(path, content) {
-            const result = {};
-            result[bobUserId] = bobKeys;
-            return { device_keys: result };
-        });
-
-        return Promise.all([
-            aliTestClient.client.downloadKeys([bobUserId, eveUserId]),
-            aliTestClient.httpBackend.flush("/keys/query", 1),
-        ]).then(function() {
-            return Promise.all([
-                aliTestClient.client.getStoredDevicesForUser(bobUserId),
-                aliTestClient.client.getStoredDevicesForUser(eveUserId),
-            ]);
-        }).then(([bobDevices, eveDevices]) => {
-            // should get an empty list
-            expect(bobDevices).toEqual([]);
-            expect(eveDevices).toEqual([]);
-        });
-    });
-
-    it("Ali gets keys with an incorrect deviceId", function() {
-        const bobDeviceKeys = {
-            algorithms: ['m.olm.v1.curve25519-aes-sha2', 'm.megolm.v1.aes-sha2'],
-            device_id: 'bad_device',
-            keys: {
-                'ed25519:bad_device': 'e8XlY5V8x2yJcwa5xpSzeC/QVOrU+D5qBgyTK0ko+f0',
-                'curve25519:bad_device': 'YxuuLG/4L5xGeP8XPl5h0d7DzyYVcof7J7do+OXz0xc',
-            },
-            user_id: '@bob:localhost',
-            signatures: {
-                '@bob:localhost': {
-                    'ed25519:bad_device': 'fEFTq67RaSoIEVBJ8DtmRovbwUBKJ0A' +
-                        'me9m9PDzM9azPUwZ38Xvf6vv1A7W1PSafH4z3Y2ORIyEnZgHaNby3CQ',
-                },
-            },
-        };
-
-        const bobKeys = {};
-        bobKeys[bobDeviceId] = bobDeviceKeys;
-        aliTestClient.httpBackend.when(
-            "POST", "/keys/query",
-        ).respond(200, function(path, content) {
-            const result = {};
-            result[bobUserId] = bobKeys;
-            return { device_keys: result };
-        });
-
-        return Promise.all([
-            aliTestClient.client.downloadKeys([bobUserId]),
-            aliTestClient.httpBackend.flush("/keys/query", 1),
-        ]).then(function() {
-            return aliTestClient.client.getStoredDevicesForUser(bobUserId);
-        }).then((devices) => {
-            // should get an empty list
-            expect(devices).toEqual([]);
-        });
-    });
-
-    it("Bob starts his client and uploads device keys and one-time keys", function() {
-        return Promise.resolve()
-            .then(() => bobTestClient.start())
-            .then(() => bobTestClient.awaitOneTimeKeyUpload())
-            .then((keys) => {
-                expect(Object.keys(keys).length).toEqual(5);
-                expect(Object.keys(bobTestClient.deviceKeys).length).not.toEqual(0);
-            });
-    });
-
-    it("Ali sends a message", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliSendsFirstMessage);
-    });
-
-    it("Bob receives a message", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliSendsFirstMessage)
-            .then(bobRecvMessage);
-    });
-
-    it("Bob receives a message with a bogus sender", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliSendsFirstMessage)
-            .then(function() {
-                const message = aliMessages.shift();
-                const syncData = {
-                    next_batch: "x",
-                    rooms: {
-                        join: {
-
-                        },
-                    },
-                };
-                syncData.rooms.join[roomId] = {
-                    timeline: {
-                        events: [
-                            testUtils.mkEvent({
-                                type: "m.room.encrypted",
-                                room: roomId,
-                                content: message,
-                                sender: "@bogus:sender",
-                            }),
-                        ],
-                    },
-                };
-                bobTestClient.httpBackend.when("GET", "/sync").respond(200, syncData);
-
-                const eventPromise = new Promise((resolve, reject) => {
-                    const onEvent = function(event) {
-                        logger.log(bobUserId + " received event",
-                                    event);
-                        resolve(event);
-                    };
-                    bobTestClient.client.once("event", onEvent);
-                });
-
-                bobTestClient.httpBackend.flush();
-                return eventPromise;
-            }).then((event) => {
-                expect(event.isEncrypted()).toBeTruthy();
-
-                // it may still be being decrypted
-                return testUtils.awaitDecryption(event);
-            }).then((event) => {
-                expect(event.getType()).toEqual("m.room.message");
-                expect(event.getContent().msgtype).toEqual("m.bad.encrypted");
-            });
-    });
-
-    it("Ali blocks Bob's device", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliDownloadsKeys)
-            .then(function() {
-                aliTestClient.client.setDeviceBlocked(bobUserId, bobDeviceId, true);
-                const p1 = sendMessage(aliTestClient.client);
-                const p2 = expectSendMessageRequest(aliTestClient.httpBackend)
-                      .then(function(sentContent) {
-                          // no unblocked devices, so the ciphertext should be empty
-                          expect(sentContent.ciphertext).toEqual({});
-                      });
-                return Promise.all([p1, p2]);
-            });
-    });
-
-    it("Bob receives two pre-key messages", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliSendsFirstMessage)
-            .then(bobRecvMessage)
-            .then(aliSendsMessage)
-            .then(bobRecvMessage);
-    });
-
-    it("Bob replies to the message", function() {
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        bobTestClient.expectKeyQuery({ device_keys: { [bobUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => bobTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(() => firstSync(bobTestClient))
-            .then(aliEnablesEncryption)
-            .then(aliSendsFirstMessage)
-            .then(bobRecvMessage)
-            .then(bobEnablesEncryption)
-            .then(bobSendsReplyMessage).then(function(ciphertext) {
-                expect(ciphertext.type).toEqual(1, "Unexpected cipghertext type.");
-            }).then(aliRecvMessage);
-    });
-
-    it("Ali does a key query when encryption is enabled", function() {
-        // enabling encryption in the room should make alice download devices
-        // for both members.
-        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} } });
-        return Promise.resolve()
-            .then(() => aliTestClient.start())
-            .then(() => firstSync(aliTestClient))
-            .then(() => {
-                const syncData = {
-                    next_batch: '2',
-                    rooms: {
-                        join: {},
-                    },
-                };
-                syncData.rooms.join[roomId] = {
-                    state: {
-                        events: [
-                            testUtils.mkEvent({
-                                type: 'm.room.encryption',
-                                skey: '',
-                                content: {
-                                    algorithm: 'm.olm.v1.curve25519-aes-sha2',
-                                },
-                            }),
-                        ],
-                    },
-                };
-
-                aliTestClient.httpBackend.when('GET', '/sync').respond(
-                    200, syncData);
-                return aliTestClient.httpBackend.flush('/sync', 1);
-            }).then(() => {
-                aliTestClient.expectKeyQuery({
-                    device_keys: {
-                        [bobUserId]: {},
-                    },
-                });
-                return aliTestClient.httpBackend.flushAllExpected();
-            });
-    });
-
-    it("Upload new oneTimeKeys based on a /sync request - no count-asking", function() {
-        // Send a response which causes a key upload
-        const httpBackend = aliTestClient.httpBackend;
-        const syncDataEmpty = {
-            next_batch: "a",
-            device_one_time_keys_count: {
-                signed_curve25519: 0,
-            },
-        };
-
-        // enqueue expectations:
-        // * Sync with empty one_time_keys => upload keys
-
-        return Promise.resolve()
-            .then(() => {
-                logger.log(aliTestClient + ': starting');
-                httpBackend.when("GET", "/versions").respond(200, {});
-                httpBackend.when("GET", "/pushrules").respond(200, {});
-                httpBackend.when("POST", "/filter").respond(200, { filter_id: "fid" });
-                aliTestClient.expectDeviceKeyUpload();
-
-                // we let the client do a very basic initial sync, which it needs before
-                // it will upload one-time keys.
-                httpBackend.when("GET", "/sync").respond(200, syncDataEmpty);
-
-                aliTestClient.client.startClient({});
-
-                return httpBackend.flushAllExpected().then(() => {
-                    logger.log(aliTestClient + ': started');
-                });
-            })
-            .then(() => httpBackend.when("POST", "/keys/upload")
-                .respond(200, (path, content) => {
-                    expect(content.one_time_keys).toBeTruthy();
-                    expect(content.one_time_keys).not.toEqual({});
-                    expect(Object.keys(content.one_time_keys).length)
-                        .toBeGreaterThanOrEqual(1);
-                    logger.log('received %i one-time keys',
-                                Object.keys(content.one_time_keys).length);
-                    // cancel futher calls by telling the client
-                    // we have more than we need
-                    return {
-                       one_time_key_counts: {
-                           signed_curve25519: 70,
-                       },
-                    };
-                }))
-            .then(() => httpBackend.flushAllExpected());
-    });
-});
@@ -0,0 +1,676 @@
+/*
+Copyright 2016 OpenMarket Ltd
+Copyright 2017 Vector Creations Ltd
+Copyright 2018 New Vector Ltd
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/* This file consists of a set of integration tests which try to simulate
+ * communication via an Olm-encrypted room between two users, Alice and Bob.
+ *
+ * Note that megolm (group) conversation is not tested here.
+ *
+ * See also `megolm.spec.js`.
+ */
+
+// load olm before the sdk if possible
+import '../olm-loader';
+
+import { logger } from '../../src/logger';
+import * as testUtils from "../test-utils/test-utils";
+import { TestClient } from "../TestClient";
+import { CRYPTO_ENABLED } from "../../src/client";
+import { ClientEvent, IContent, ISendEventResponse, MatrixClient, MatrixEvent } from "../../src/matrix";
+
+let aliTestClient: TestClient;
+const roomId = "!room:localhost";
+const aliUserId = "@ali:localhost";
+const aliDeviceId = "zxcvb";
+const aliAccessToken = "aseukfgwef";
+let bobTestClient: TestClient;
+const bobUserId = "@bob:localhost";
+const bobDeviceId = "bvcxz";
+const bobAccessToken = "fewgfkuesa";
+let aliMessages: IContent[];
+let bobMessages: IContent[];
+
+// IMessage isn't exported by src/crypto/algorithms/olm.ts
+interface OlmPayload {
+    type: number;
+    body: string;
+}
+
+async function bobUploadsDeviceKeys(): Promise<void> {
+    bobTestClient.expectDeviceKeyUpload();
+    await Promise.all([
+        bobTestClient.client.uploadKeys(),
+        bobTestClient.httpBackend.flushAllExpected(),
+    ]);
+    expect(Object.keys(bobTestClient.deviceKeys).length).not.toEqual(0);
+}
+
+/**
+ * Set an expectation that querier will query uploader's keys; then flush the http request.
+ *
+ * @return {promise} resolves once the http request has completed.
+ */
+function expectQueryKeys(querier: TestClient, uploader: TestClient): Promise<number> {
+    // can't query keys before bob has uploaded them
+    expect(uploader.deviceKeys).toBeTruthy();
+
+    const uploaderKeys = {};
+    uploaderKeys[uploader.deviceId] = uploader.deviceKeys;
+    querier.httpBackend.when("POST", "/keys/query")
+        .respond(200, function(_path, content) {
+            expect(content.device_keys[uploader.userId]).toEqual([]);
+            const result = {};
+            result[uploader.userId] = uploaderKeys;
+            return { device_keys: result };
+        });
+    return querier.httpBackend.flush("/keys/query", 1);
+}
+const expectAliQueryKeys = () => expectQueryKeys(aliTestClient, bobTestClient);
+const expectBobQueryKeys = () => expectQueryKeys(bobTestClient, aliTestClient);
+
+/**
+ * Set an expectation that ali will claim one of bob's keys; then flush the http request.
+ *
+ * @return {promise} resolves once the http request has completed.
+ */
+async function expectAliClaimKeys(): Promise<void> {
+    const keys = await bobTestClient.awaitOneTimeKeyUpload();
+    aliTestClient.httpBackend.when(
+        "POST", "/keys/claim",
+    ).respond(200, function(_path, content) {
+        const claimType = content.one_time_keys[bobUserId][bobDeviceId];
+        expect(claimType).toEqual("signed_curve25519");
+        let keyId = null;
+        for (keyId in keys) {
+            if (bobTestClient.oneTimeKeys.hasOwnProperty(keyId)) {
+                if (keyId.indexOf(claimType + ":") === 0) {
+                    break;
+                }
+            }
+        }
+        const result = {};
+        result[bobUserId] = {};
+        result[bobUserId][bobDeviceId] = {};
+        result[bobUserId][bobDeviceId][keyId] = keys[keyId];
+        return { one_time_keys: result };
+    });
+    // it can take a while to process the key query, so give it some extra
+    // time, and make sure the claim actually happens rather than ploughing on
+    // confusingly.
+    const r = await aliTestClient.httpBackend.flush("/keys/claim", 1, 500);
+    expect(r).toEqual(1);
+}
+
+async function aliDownloadsKeys(): Promise<void> {
+    // can't query keys before bob has uploaded them
+    expect(bobTestClient.getSigningKey()).toBeTruthy();
+
+    const p1 = async () => {
+        await aliTestClient.client.downloadKeys([bobUserId]);
+        const devices = aliTestClient.client.getStoredDevicesForUser(bobUserId);
+        expect(devices.length).toEqual(1);
+        expect(devices[0].deviceId).toEqual("bvcxz");
+    };
+    const p2 = expectAliQueryKeys;
+
+    // check that the localStorage is updated as we expect (not sure this is
+    // an integration test, but meh)
+    await Promise.all([p1(), p2()]);
+    await aliTestClient.client.crypto.deviceList.saveIfDirty();
+    // @ts-ignore - protected
+    aliTestClient.client.cryptoStore.getEndToEndDeviceData(null, (data) => {
+        const devices = data.devices[bobUserId];
+        expect(devices[bobDeviceId].keys).toEqual(bobTestClient.deviceKeys.keys);
+        expect(devices[bobDeviceId].verified).
+            toBe(0); // DeviceVerification.UNVERIFIED
+    });
+}
+
+async function clientEnablesEncryption(client: MatrixClient): Promise<void> {
+    await client.setRoomEncryption(roomId, {
+        algorithm: "m.olm.v1.curve25519-aes-sha2",
+    });
+    expect(client.isRoomEncrypted(roomId)).toBeTruthy();
+}
+const aliEnablesEncryption = () => clientEnablesEncryption(aliTestClient.client);
+const bobEnablesEncryption = () => clientEnablesEncryption(bobTestClient.client);
+
+/**
+ * Ali sends a message, first claiming e2e keys. Set the expectations and
+ * check the results.
+ *
+ * @return {promise} which resolves to the ciphertext for Bob's device.
+ */
+async function aliSendsFirstMessage(): Promise<OlmPayload> {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    const [_, ciphertext] = await Promise.all([
+        sendMessage(aliTestClient.client),
+        expectAliQueryKeys()
+            .then(expectAliClaimKeys)
+            .then(expectAliSendMessageRequest),
+    ]);
+    return ciphertext;
+}
+
+/**
+ * Ali sends a message without first claiming e2e keys. Set the expectations
+ * and check the results.
+ *
+ * @return {promise} which resolves to the ciphertext for Bob's device.
+ */
+async function aliSendsMessage(): Promise<OlmPayload> {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    const [_, ciphertext] = await Promise.all([
+        sendMessage(aliTestClient.client),
+        expectAliSendMessageRequest(),
+    ]);
+    return ciphertext;
+}
+
+/**
+ * Bob sends a message, first querying (but not claiming) e2e keys. Set the
+ * expectations and check the results.
+ *
+ * @return {promise} which resolves to the ciphertext for Ali's device.
+ */
+async function bobSendsReplyMessage(): Promise<OlmPayload> {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    const [_, ciphertext] = await Promise.all([
+        sendMessage(bobTestClient.client),
+        expectBobQueryKeys()
+            .then(expectBobSendMessageRequest),
+    ]);
+    return ciphertext;
+}
+
+/**
+ * Set an expectation that Ali will send a message, and flush the request
+ *
+ * @return {promise} which resolves to the ciphertext for Bob's device.
+ */
+async function expectAliSendMessageRequest(): Promise<OlmPayload> {
+    const content = await expectSendMessageRequest(aliTestClient.httpBackend);
+    aliMessages.push(content);
+    expect(Object.keys(content.ciphertext)).toEqual([bobTestClient.getDeviceKey()]);
+    const ciphertext = content.ciphertext[bobTestClient.getDeviceKey()];
+    expect(ciphertext).toBeTruthy();
+    return ciphertext;
+}
+
+/**
+ * Set an expectation that Bob will send a message, and flush the request
+ *
+ * @return {promise} which resolves to the ciphertext for Bob's device.
+ */
+async function expectBobSendMessageRequest(): Promise<OlmPayload> {
+    const content = await expectSendMessageRequest(bobTestClient.httpBackend);
+    bobMessages.push(content);
+    const aliKeyId = "curve25519:" + aliDeviceId;
+    const aliDeviceCurve25519Key = aliTestClient.deviceKeys.keys[aliKeyId];
+    expect(Object.keys(content.ciphertext)).toEqual([aliDeviceCurve25519Key]);
+    const ciphertext = content.ciphertext[aliDeviceCurve25519Key];
+    expect(ciphertext).toBeTruthy();
+    return ciphertext;
+}
+
+function sendMessage(client: MatrixClient): Promise<ISendEventResponse> {
+    return client.sendMessage(
+        roomId, { msgtype: "m.text", body: "Hello, World" },
+    );
+}
+
+async function expectSendMessageRequest(httpBackend: TestClient["httpBackend"]): Promise<IContent> {
+    const path = "/send/m.room.encrypted/";
+    const prom = new Promise((resolve) => {
+        httpBackend.when("PUT", path).respond(200, function(_path, content) {
+            resolve(content);
+            return {
+                event_id: "asdfgh",
+            };
+        });
+    });
+
+    // it can take a while to process the key query
+    await httpBackend.flush(path, 1);
+    return prom;
+}
+
+function aliRecvMessage(): Promise<void> {
+    const message = bobMessages.shift();
+    return recvMessage(
+        aliTestClient.httpBackend, aliTestClient.client, bobUserId, message,
+    );
+}
+
+function bobRecvMessage(): Promise<void> {
+    const message = aliMessages.shift();
+    return recvMessage(
+        bobTestClient.httpBackend, bobTestClient.client, aliUserId, message,
+    );
+}
+
+async function recvMessage(
+    httpBackend: TestClient["httpBackend"],
+    client: MatrixClient,
+    sender: string,
+    message: IContent,
+): Promise<void> {
+    const syncData = {
+        next_batch: "x",
+        rooms: {
+            join: {
+
+            },
+        },
+    };
+    syncData.rooms.join[roomId] = {
+        timeline: {
+            events: [
+                testUtils.mkEvent({
+                    type: "m.room.encrypted",
+                    room: roomId,
+                    content: message,
+                    sender: sender,
+                }),
+            ],
+        },
+    };
+    httpBackend.when("GET", "/sync").respond(200, syncData);
+
+    const eventPromise = new Promise<MatrixEvent>((resolve) => {
+        const onEvent = function(event: MatrixEvent) {
+            // ignore the m.room.member events
+            if (event.getType() == "m.room.member") {
+                return;
+            }
+            logger.log(client.credentials.userId + " received event",
+                event);
+
+            client.removeListener(ClientEvent.Event, onEvent);
+            resolve(event);
+        };
+        client.on(ClientEvent.Event, onEvent);
+    });
+
+    await httpBackend.flushAllExpected();
+
+    const preDecryptionEvent = await eventPromise;
+    expect(preDecryptionEvent.isEncrypted()).toBeTruthy();
+    // it may still be being decrypted
+    const event = await testUtils.awaitDecryption(preDecryptionEvent);
+    expect(event.getType()).toEqual("m.room.message");
+    expect(event.getContent()).toMatchObject({
+        msgtype: "m.text",
+        body: "Hello, World",
+    });
+    expect(event.isEncrypted()).toBeTruthy();
+}
+
+/**
+ * Send an initial sync response to the client (which just includes the member
+ * list for our test room).
+ *
+ * @param {TestClient} testClient
+ * @returns {Promise} which resolves when the sync has been flushed.
+ */
+function firstSync(testClient: TestClient): Promise<void> {
+    // send a sync response including our test room.
+    const syncData = {
+        next_batch: "x",
+        rooms: {
+            join: { },
+        },
+    };
+    syncData.rooms.join[roomId] = {
+        state: {
+            events: [
+                testUtils.mkMembership({
+                    mship: "join",
+                    user: aliUserId,
+                }),
+                testUtils.mkMembership({
+                    mship: "join",
+                    user: bobUserId,
+                }),
+            ],
+        },
+        timeline: {
+            events: [],
+        },
+    };
+
+    testClient.httpBackend.when("GET", "/sync").respond(200, syncData);
+    return testClient.flushSync();
+}
+
+describe("MatrixClient crypto", () => {
+    if (!CRYPTO_ENABLED) {
+        return;
+    }
+
+    beforeEach(async () => {
+        aliTestClient = new TestClient(aliUserId, aliDeviceId, aliAccessToken);
+        await aliTestClient.client.initCrypto();
+
+        bobTestClient = new TestClient(bobUserId, bobDeviceId, bobAccessToken);
+        await bobTestClient.client.initCrypto();
+
+        aliMessages = [];
+        bobMessages = [];
+    });
+
+    afterEach(() => {
+        aliTestClient.httpBackend.verifyNoOutstandingExpectation();
+        bobTestClient.httpBackend.verifyNoOutstandingExpectation();
+
+        return Promise.all([aliTestClient.stop(), bobTestClient.stop()]);
+    });
+
+    it("Bob uploads device keys", bobUploadsDeviceKeys);
+
+    it("Ali downloads Bobs device keys", async () => {
+        await bobUploadsDeviceKeys();
+        await aliDownloadsKeys();
+    });
+
+    it("Ali gets keys with an invalid signature", async () => {
+        await bobUploadsDeviceKeys();
+        // tamper bob's keys
+        const bobDeviceKeys = bobTestClient.deviceKeys;
+        expect(bobDeviceKeys.keys["curve25519:" + bobDeviceId]).toBeTruthy();
+        bobDeviceKeys.keys["curve25519:" + bobDeviceId] += "abc";
+        await Promise.all([
+            aliTestClient.client.downloadKeys([bobUserId]),
+            expectAliQueryKeys(),
+        ]);
+        const devices = aliTestClient.client.getStoredDevicesForUser(bobUserId);
+        // should get an empty list
+        expect(devices).toEqual([]);
+    });
+
+    it("Ali gets keys with an incorrect userId", async () => {
+        const eveUserId = "@eve:localhost";
+
+        const bobDeviceKeys = {
+            algorithms: ['m.olm.v1.curve25519-aes-sha2', 'm.megolm.v1.aes-sha2'],
+            device_id: 'bvcxz',
+            keys: {
+                'ed25519:bvcxz': 'pYuWKMCVuaDLRTM/eWuB8OlXEb61gZhfLVJ+Y54tl0Q',
+                'curve25519:bvcxz': '7Gni0loo/nzF0nFp9847RbhElGewzwUXHPrljjBGPTQ',
+            },
+            user_id: '@eve:localhost',
+            signatures: {
+                '@eve:localhost': {
+                    'ed25519:bvcxz': 'CliUPZ7dyVPBxvhSA1d+X+LYa5b2AYdjcTwG' +
+                        '0stXcIxjaJNemQqtdgwKDtBFl3pN2I13SEijRDCf1A8bYiQMDg',
+                },
+            },
+        };
+
+        const bobKeys = {};
+        bobKeys[bobDeviceId] = bobDeviceKeys;
+        aliTestClient.httpBackend.when(
+            "POST", "/keys/query",
+        ).respond(200, { device_keys: { [bobUserId]: bobKeys } });
+
+        await Promise.all([
+            aliTestClient.client.downloadKeys([bobUserId, eveUserId]),
+            aliTestClient.httpBackend.flush("/keys/query", 1),
+        ]);
+        const [bobDevices, eveDevices] = await Promise.all([
+            aliTestClient.client.getStoredDevicesForUser(bobUserId),
+            aliTestClient.client.getStoredDevicesForUser(eveUserId),
+        ]);
+        // should get an empty list
+        expect(bobDevices).toEqual([]);
+        expect(eveDevices).toEqual([]);
+    });
+
+    it("Ali gets keys with an incorrect deviceId", async () => {
+        const bobDeviceKeys = {
+            algorithms: ['m.olm.v1.curve25519-aes-sha2', 'm.megolm.v1.aes-sha2'],
+            device_id: 'bad_device',
+            keys: {
+                'ed25519:bad_device': 'e8XlY5V8x2yJcwa5xpSzeC/QVOrU+D5qBgyTK0ko+f0',
+                'curve25519:bad_device': 'YxuuLG/4L5xGeP8XPl5h0d7DzyYVcof7J7do+OXz0xc',
+            },
+            user_id: '@bob:localhost',
+            signatures: {
+                '@bob:localhost': {
+                    'ed25519:bad_device': 'fEFTq67RaSoIEVBJ8DtmRovbwUBKJ0A' +
+                        'me9m9PDzM9azPUwZ38Xvf6vv1A7W1PSafH4z3Y2ORIyEnZgHaNby3CQ',
+                },
+            },
+        };
+
+        const bobKeys = {};
+        bobKeys[bobDeviceId] = bobDeviceKeys;
+        aliTestClient.httpBackend.when(
+            "POST", "/keys/query",
+        ).respond(200, { device_keys: { [bobUserId]: bobKeys } });
+
+        await Promise.all([
+            aliTestClient.client.downloadKeys([bobUserId]),
+            aliTestClient.httpBackend.flush("/keys/query", 1),
+        ]);
+        const devices = aliTestClient.client.getStoredDevicesForUser(bobUserId);
+        // should get an empty list
+        expect(devices).toEqual([]);
+    });
+
+    it("Bob starts his client and uploads device keys and one-time keys", async () => {
+        await bobTestClient.start();
+        const keys = await bobTestClient.awaitOneTimeKeyUpload();
+        expect(Object.keys(keys).length).toEqual(5);
+        expect(Object.keys(bobTestClient.deviceKeys).length).not.toEqual(0);
+    });
+
+    it("Ali sends a message", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await aliEnablesEncryption();
+        await aliSendsFirstMessage();
+    });
+
+    it("Bob receives a message", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await aliEnablesEncryption();
+        await aliSendsFirstMessage();
+        await bobRecvMessage();
+    });
+
+    it("Bob receives a message with a bogus sender", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await aliEnablesEncryption();
+        await aliSendsFirstMessage();
+        const message = aliMessages.shift();
+        const syncData = {
+            next_batch: "x",
+            rooms: {
+                join: {
+
+                },
+            },
+        };
+        syncData.rooms.join[roomId] = {
+            timeline: {
+                events: [
+                    testUtils.mkEvent({
+                        type: "m.room.encrypted",
+                        room: roomId,
+                        content: message,
+                        sender: "@bogus:sender",
+                    }),
+                ],
+            },
+        };
+        bobTestClient.httpBackend.when("GET", "/sync").respond(200, syncData);
+
+        const eventPromise = new Promise<MatrixEvent>((resolve) => {
+            const onEvent = function(event: MatrixEvent) {
+                logger.log(bobUserId + " received event", event);
+                resolve(event);
+            };
+            bobTestClient.client.once(ClientEvent.Event, onEvent);
+        });
+        await bobTestClient.httpBackend.flushAllExpected();
+        const preDecryptionEvent = await eventPromise;
+        expect(preDecryptionEvent.isEncrypted()).toBeTruthy();
+        // it may still be being decrypted
+        const event = await testUtils.awaitDecryption(preDecryptionEvent);
+        expect(event.getType()).toEqual("m.room.message");
+        expect(event.getContent().msgtype).toEqual("m.bad.encrypted");
+    });
+
+    it("Ali blocks Bob's device", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await aliEnablesEncryption();
+        await aliDownloadsKeys();
+        aliTestClient.client.setDeviceBlocked(bobUserId, bobDeviceId, true);
+        const p1 = sendMessage(aliTestClient.client);
+        const p2 = expectSendMessageRequest(aliTestClient.httpBackend)
+            .then(function(sentContent) {
+                // no unblocked devices, so the ciphertext should be empty
+                expect(sentContent.ciphertext).toEqual({});
+            });
+        await Promise.all([p1, p2]);
+    });
+
+    it("Bob receives two pre-key messages", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await aliEnablesEncryption();
+        await aliSendsFirstMessage();
+        await bobRecvMessage();
+        await aliSendsMessage();
+        await bobRecvMessage();
+    });
+
+    it("Bob replies to the message", async () => {
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        bobTestClient.expectKeyQuery({ device_keys: { [bobUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await bobTestClient.start();
+        await firstSync(aliTestClient);
+        await firstSync(bobTestClient);
+        await aliEnablesEncryption();
+        await aliSendsFirstMessage();
+        await bobRecvMessage();
+        await bobEnablesEncryption();
+        const ciphertext = await bobSendsReplyMessage();
+        expect(ciphertext.type).toEqual(1);
+        await aliRecvMessage();
+    });
+
+    it("Ali does a key query when encryption is enabled", async () => {
+        // enabling encryption in the room should make alice download devices
+        // for both members.
+        aliTestClient.expectKeyQuery({ device_keys: { [aliUserId]: {} }, failures: {} });
+        await aliTestClient.start();
+        await firstSync(aliTestClient);
+        const syncData = {
+            next_batch: '2',
+            rooms: {
+                join: {},
+            },
+        };
+        syncData.rooms.join[roomId] = {
+            state: {
+                events: [
+                    testUtils.mkEvent({
+                        type: 'm.room.encryption',
+                        skey: '',
+                        content: {
+                            algorithm: 'm.olm.v1.curve25519-aes-sha2',
+                        },
+                    }),
+                ],
+            },
+        };
+
+        aliTestClient.httpBackend.when('GET', '/sync').respond(
+            200, syncData);
+        await aliTestClient.httpBackend.flush('/sync', 1);
+        aliTestClient.expectKeyQuery({
+            device_keys: {
+                [bobUserId]: {},
+            },
+            failures: {},
+        });
+        await aliTestClient.httpBackend.flushAllExpected();
+    });
+
+    it("Upload new oneTimeKeys based on a /sync request - no count-asking", async () => {
+        // Send a response which causes a key upload
+        const httpBackend = aliTestClient.httpBackend;
+        const syncDataEmpty = {
+            next_batch: "a",
+            device_one_time_keys_count: {
+                signed_curve25519: 0,
+            },
+        };
+
+        // enqueue expectations:
+        // * Sync with empty one_time_keys => upload keys
+
+        logger.log(aliTestClient + ': starting');
+        httpBackend.when("GET", "/versions").respond(200, {});
+        httpBackend.when("GET", "/pushrules").respond(200, {});
+        httpBackend.when("POST", "/filter").respond(200, { filter_id: "fid" });
+        aliTestClient.expectDeviceKeyUpload();
+
+        // we let the client do a very basic initial sync, which it needs before
+        // it will upload one-time keys.
+        httpBackend.when("GET", "/sync").respond(200, syncDataEmpty);
+
+        await Promise.all([
+            aliTestClient.client.startClient({}),
+            httpBackend.flushAllExpected(),
+        ]);
+        logger.log(aliTestClient + ': started');
+        httpBackend.when("POST", "/keys/upload")
+            .respond(200, (_path, content) => {
+                expect(content.one_time_keys).toBeTruthy();
+                expect(content.one_time_keys).not.toEqual({});
+                expect(Object.keys(content.one_time_keys).length).toBeGreaterThanOrEqual(1);
+                logger.log('received %i one-time keys', Object.keys(content.one_time_keys).length);
+                // cancel futher calls by telling the client
+                // we have more than we need
+                return {
+                    one_time_key_counts: {
+                        signed_curve25519: 70,
+                    },
+                };
+            });
+        await httpBackend.flushAllExpected();
+    });
+});
@@ -0,0 +1,763 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// eslint-disable-next-line no-restricted-imports
+import MockHttpBackend from "matrix-mock-request";
+import { fail } from "assert";
+
+import { SlidingSync, SlidingSyncEvent, MSC3575RoomData, SlidingSyncState, Extension } from "../../src/sliding-sync";
+import { TestClient } from "../TestClient";
+import { IRoomEvent, IStateEvent } from "../../src/sync-accumulator";
+import {
+    MatrixClient, MatrixEvent, NotificationCountType, JoinRule, MatrixError,
+    EventType, IPushRules, PushRuleKind, TweakName, ClientEvent,
+} from "../../src";
+import { SlidingSyncSdk } from "../../src/sliding-sync-sdk";
+import { SyncState } from "../../src/sync";
+import { IStoredClientOpts } from "../../src/client";
+import { logger } from "../../src/logger";
+
+describe("SlidingSyncSdk", () => {
+    let client: MatrixClient = null;
+    let httpBackend: MockHttpBackend = null;
+    let sdk: SlidingSyncSdk = null;
+    let mockSlidingSync: SlidingSync = null;
+    const selfUserId = "@alice:localhost";
+    const selfAccessToken = "aseukfgwef";
+
+    const mockifySlidingSync = (s: SlidingSync): SlidingSync => {
+        s.getList = jest.fn();
+        s.getListData = jest.fn();
+        s.getRoomSubscriptions = jest.fn();
+        s.listLength = jest.fn();
+        s.modifyRoomSubscriptionInfo = jest.fn();
+        s.modifyRoomSubscriptions = jest.fn();
+        s.registerExtension = jest.fn();
+        s.setList = jest.fn();
+        s.setListRanges = jest.fn();
+        s.start = jest.fn();
+        s.stop = jest.fn();
+        s.resend = jest.fn();
+        return s;
+    };
+
+    // shorthand way to make events without filling in all the fields
+    let eventIdCounter = 0;
+    const mkOwnEvent = (evType: string, content: object): IRoomEvent => {
+        eventIdCounter++;
+        return {
+            type: evType,
+            content: content,
+            sender: selfUserId,
+            origin_server_ts: Date.now(),
+            event_id: "$" + eventIdCounter,
+        };
+    };
+    const mkOwnStateEvent = (evType: string, content: object, stateKey?: string): IStateEvent => {
+        eventIdCounter++;
+        return {
+            type: evType,
+            state_key: stateKey,
+            content: content,
+            sender: selfUserId,
+            origin_server_ts: Date.now(),
+            event_id: "$" + eventIdCounter,
+        };
+    };
+    const assertTimelineEvents = (got: MatrixEvent[], want: IRoomEvent[]): void => {
+        expect(got.length).toEqual(want.length);
+        got.forEach((m, i) => {
+            expect(m.getType()).toEqual(want[i].type);
+            expect(m.getSender()).toEqual(want[i].sender);
+            expect(m.getId()).toEqual(want[i].event_id);
+            expect(m.getContent()).toEqual(want[i].content);
+            expect(m.getTs()).toEqual(want[i].origin_server_ts);
+            if (want[i].unsigned) {
+                expect(m.getUnsigned()).toEqual(want[i].unsigned);
+            }
+            const maybeStateEvent = want[i] as IStateEvent;
+            if (maybeStateEvent.state_key) {
+                expect(m.getStateKey()).toEqual(maybeStateEvent.state_key);
+            }
+        });
+    };
+
+    // assign client/httpBackend globals
+    const setupClient = async (testOpts?: Partial<IStoredClientOpts&{withCrypto: boolean}>) => {
+        testOpts = testOpts || {};
+        const testClient = new TestClient(selfUserId, "DEVICE", selfAccessToken);
+        httpBackend = testClient.httpBackend;
+        client = testClient.client;
+        mockSlidingSync = mockifySlidingSync(new SlidingSync("", [], {}, client, 0));
+        if (testOpts.withCrypto) {
+            httpBackend.when("GET", "/room_keys/version").respond(404, {});
+            await client.initCrypto();
+            testOpts.crypto = client.crypto;
+        }
+        httpBackend.when("GET", "/_matrix/client/r0/pushrules").respond(200, {});
+        sdk = new SlidingSyncSdk(mockSlidingSync, client, testOpts);
+    };
+
+    // tear down client/httpBackend globals
+    const teardownClient = () => {
+        client.stopClient();
+        return httpBackend.stop();
+    };
+
+    // find an extension on a SlidingSyncSdk instance
+    const findExtension = (name: string): Extension => {
+        expect(mockSlidingSync.registerExtension).toHaveBeenCalled();
+        const mockFn = mockSlidingSync.registerExtension as jest.Mock;
+        // find the extension
+        for (let i = 0; i < mockFn.mock.calls.length; i++) {
+            const calledExtension = mockFn.mock.calls[i][0] as Extension;
+            if (calledExtension && calledExtension.name() === name) {
+                return calledExtension;
+            }
+        }
+        fail("cannot find extension " + name);
+    };
+
+    describe("sync/stop", () => {
+        beforeAll(async () => {
+            await setupClient();
+        });
+        afterAll(teardownClient);
+        it("can sync()", async () => {
+            const hasSynced = sdk.sync();
+            await httpBackend.flushAllExpected();
+            await hasSynced;
+            expect(mockSlidingSync.start).toBeCalled();
+        });
+        it("can stop()", async () => {
+            sdk.stop();
+            expect(mockSlidingSync.stop).toBeCalled();
+        });
+    });
+
+    describe("rooms", () => {
+        beforeAll(async () => {
+            await setupClient();
+        });
+        afterAll(teardownClient);
+
+        describe("initial", () => {
+            beforeAll(async () => {
+                const hasSynced = sdk.sync();
+                await httpBackend.flushAllExpected();
+                await hasSynced;
+            });
+            // inject some rooms with different fields set.
+            // All rooms are new so they all have initial: true
+            const roomA = "!a_state_and_timeline:localhost";
+            const roomB = "!b_timeline_only:localhost";
+            const roomC = "!c_with_highlight_count:localhost";
+            const roomD = "!d_with_notif_count:localhost";
+            const roomE = "!e_with_invite:localhost";
+            const roomF = "!f_calc_room_name:localhost";
+            const data: Record<string, MSC3575RoomData> = {
+                [roomA]: {
+                    name: "A",
+                    required_state: [
+                        mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                        mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                        mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                        mkOwnStateEvent(EventType.RoomName, { name: "A" }, ""),
+                    ],
+                    timeline: [
+                        mkOwnEvent(EventType.RoomMessage, { body: "hello A" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "world A" }),
+                    ],
+                    initial: true,
+                },
+                [roomB]: {
+                    name: "B",
+                    required_state: [],
+                    timeline: [
+                        mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                        mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                        mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                        mkOwnEvent(EventType.RoomMessage, { body: "hello B" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "world B" }),
+
+                    ],
+                    initial: true,
+                },
+                [roomC]: {
+                    name: "C",
+                    required_state: [],
+                    timeline: [
+                        mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                        mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                        mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                        mkOwnEvent(EventType.RoomMessage, { body: "hello C" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "world C" }),
+                    ],
+                    highlight_count: 5,
+                    initial: true,
+                },
+                [roomD]: {
+                    name: "D",
+                    required_state: [],
+                    timeline: [
+                        mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                        mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                        mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                        mkOwnEvent(EventType.RoomMessage, { body: "hello D" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "world D" }),
+                    ],
+                    notification_count: 5,
+                    initial: true,
+                },
+                [roomE]: {
+                    name: "E",
+                    required_state: [],
+                    timeline: [],
+                    invite_state: [
+                        {
+                            type: EventType.RoomMember,
+                            content: { membership: "invite" },
+                            state_key: selfUserId,
+                            sender: "@bob:localhost",
+                            event_id: "$room_e_invite",
+                            origin_server_ts: 123456,
+                        },
+                        {
+                            type: "m.room.join_rules",
+                            content: { join_rule: "invite" },
+                            state_key: "",
+                            sender: "@bob:localhost",
+                            event_id: "$room_e_join_rule",
+                            origin_server_ts: 123456,
+                        },
+                    ],
+                    initial: true,
+                },
+                [roomF]: {
+                    name: "#foo:localhost",
+                    required_state: [
+                        mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                        mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                        mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                        mkOwnStateEvent(EventType.RoomCanonicalAlias, { alias: "#foo:localhost" }, ""),
+                        mkOwnStateEvent(EventType.RoomName, { name: "This should be ignored" }, ""),
+                    ],
+                    timeline: [
+                        mkOwnEvent(EventType.RoomMessage, { body: "hello A" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "world A" }),
+                    ],
+                    initial: true,
+                },
+            };
+
+            it("can be created with required_state and timeline", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomA, data[roomA]);
+                const gotRoom = client.getRoom(roomA);
+                expect(gotRoom).toBeDefined();
+                expect(gotRoom.name).toEqual(data[roomA].name);
+                expect(gotRoom.getMyMembership()).toEqual("join");
+                assertTimelineEvents(gotRoom.getLiveTimeline().getEvents().slice(-2), data[roomA].timeline);
+            });
+
+            it("can be created with timeline only", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomB, data[roomB]);
+                const gotRoom = client.getRoom(roomB);
+                expect(gotRoom).toBeDefined();
+                expect(gotRoom.name).toEqual(data[roomB].name);
+                expect(gotRoom.getMyMembership()).toEqual("join");
+                assertTimelineEvents(gotRoom.getLiveTimeline().getEvents().slice(-5), data[roomB].timeline);
+            });
+
+            it("can be created with a highlight_count", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomC, data[roomC]);
+                const gotRoom = client.getRoom(roomC);
+                expect(gotRoom).toBeDefined();
+                expect(
+                    gotRoom.getUnreadNotificationCount(NotificationCountType.Highlight),
+                ).toEqual(data[roomC].highlight_count);
+            });
+
+            it("can be created with a notification_count", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomD, data[roomD]);
+                const gotRoom = client.getRoom(roomD);
+                expect(gotRoom).toBeDefined();
+                expect(
+                    gotRoom.getUnreadNotificationCount(NotificationCountType.Total),
+                ).toEqual(data[roomD].notification_count);
+            });
+
+            it("can be created with invite_state", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomE, data[roomE]);
+                const gotRoom = client.getRoom(roomE);
+                expect(gotRoom).toBeDefined();
+                expect(gotRoom.getMyMembership()).toEqual("invite");
+                expect(gotRoom.currentState.getJoinRule()).toEqual(JoinRule.Invite);
+            });
+
+            it("uses the 'name' field to caluclate the room name", () => {
+                mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomF, data[roomF]);
+                const gotRoom = client.getRoom(roomF);
+                expect(gotRoom).toBeDefined();
+                expect(
+                    gotRoom.name,
+                ).toEqual(data[roomF].name);
+            });
+
+            describe("updating", () => {
+                it("can update with a new timeline event", async () => {
+                    const newEvent = mkOwnEvent(EventType.RoomMessage, { body: "new event A" });
+                    mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomA, {
+                        timeline: [newEvent],
+                        required_state: [],
+                        name: data[roomA].name,
+                    });
+                    const gotRoom = client.getRoom(roomA);
+                    expect(gotRoom).toBeDefined();
+                    const newTimeline = data[roomA].timeline;
+                    newTimeline.push(newEvent);
+                    assertTimelineEvents(gotRoom.getLiveTimeline().getEvents().slice(-3), newTimeline);
+                });
+
+                it("can update with a new required_state event", async () => {
+                    let gotRoom = client.getRoom(roomB);
+                    expect(gotRoom.getJoinRule()).toEqual(JoinRule.Invite); // default
+                    mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomB, {
+                        required_state: [
+                            mkOwnStateEvent("m.room.join_rules", { join_rule: "restricted" }, ""),
+                        ],
+                        timeline: [],
+                        name: data[roomB].name,
+                    });
+                    gotRoom = client.getRoom(roomB);
+                    expect(gotRoom).toBeDefined();
+                    expect(gotRoom.getJoinRule()).toEqual(JoinRule.Restricted);
+                });
+
+                it("can update with a new highlight_count", async () => {
+                    mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomC, {
+                        name: data[roomC].name,
+                        required_state: [],
+                        timeline: [],
+                        highlight_count: 1,
+                    });
+                    const gotRoom = client.getRoom(roomC);
+                    expect(gotRoom).toBeDefined();
+                    expect(
+                        gotRoom.getUnreadNotificationCount(NotificationCountType.Highlight),
+                    ).toEqual(1);
+                });
+
+                it("can update with a new notification_count", async () => {
+                    mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomD, {
+                        name: data[roomD].name,
+                        required_state: [],
+                        timeline: [],
+                        notification_count: 1,
+                    });
+                    const gotRoom = client.getRoom(roomD);
+                    expect(gotRoom).toBeDefined();
+                    expect(
+                        gotRoom.getUnreadNotificationCount(NotificationCountType.Total),
+                    ).toEqual(1);
+                });
+
+                // Regression test for a bug which caused the timeline entries to be out-of-order
+                // when the same room appears twice with different timeline limits. E.g appears in
+                // the list with timeline_limit:1 then appears again as a room subscription with
+                // timeline_limit:50
+                it("can return history with a larger timeline_limit", async () => {
+                    const timeline = data[roomA].timeline;
+                    const oldTimeline = [
+                        mkOwnEvent(EventType.RoomMessage, { body: "old event A" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "old event B" }),
+                        mkOwnEvent(EventType.RoomMessage, { body: "old event C" }),
+                        ...timeline,
+                    ];
+                    mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomA, {
+                        timeline: oldTimeline,
+                        required_state: [],
+                        name: data[roomA].name,
+                        initial: true, // e.g requested via room subscription
+                    });
+                    const gotRoom = client.getRoom(roomA);
+                    expect(gotRoom).toBeDefined();
+
+                    logger.log("want:", oldTimeline.map((e) => (e.type + " : " + (e.content || {}).body)));
+                    logger.log("got:", gotRoom.getLiveTimeline().getEvents().map(
+                        (e) => (e.getType() + " : " + e.getContent().body)),
+                    );
+
+                    // we expect the timeline now to be oldTimeline (so the old events are in fact old)
+                    assertTimelineEvents(gotRoom.getLiveTimeline().getEvents(), oldTimeline);
+                });
+            });
+        });
+    });
+
+    describe("lifecycle", () => {
+        beforeAll(async () => {
+            await setupClient();
+            const hasSynced = sdk.sync();
+            await httpBackend.flushAllExpected();
+            await hasSynced;
+        });
+        const FAILED_SYNC_ERROR_THRESHOLD = 3; // would be nice to export the const in the actual class...
+
+        it("emits SyncState.Reconnecting when < FAILED_SYNC_ERROR_THRESHOLD & SyncState.Error when over", async () => {
+            mockSlidingSync.emit(
+                SlidingSyncEvent.Lifecycle, SlidingSyncState.Complete,
+                { pos: "h", lists: [], rooms: {}, extensions: {} }, null,
+            );
+            expect(sdk.getSyncState()).toEqual(SyncState.Syncing);
+
+            mockSlidingSync.emit(
+                SlidingSyncEvent.Lifecycle, SlidingSyncState.RequestFinished, null, new Error("generic"),
+            );
+            expect(sdk.getSyncState()).toEqual(SyncState.Reconnecting);
+
+            for (let i = 0; i < FAILED_SYNC_ERROR_THRESHOLD; i++) {
+                mockSlidingSync.emit(
+                    SlidingSyncEvent.Lifecycle, SlidingSyncState.RequestFinished, null, new Error("generic"),
+                );
+            }
+            expect(sdk.getSyncState()).toEqual(SyncState.Error);
+        });
+
+        it("emits SyncState.Syncing after a previous SyncState.Error", async () => {
+            mockSlidingSync.emit(
+                SlidingSyncEvent.Lifecycle,
+                SlidingSyncState.Complete,
+                { pos: "i", lists: [], rooms: {}, extensions: {} },
+                null,
+            );
+            expect(sdk.getSyncState()).toEqual(SyncState.Syncing);
+        });
+
+        it("emits SyncState.Error immediately when receiving M_UNKNOWN_TOKEN and stops syncing", async () => {
+            expect(mockSlidingSync.stop).not.toBeCalled();
+            mockSlidingSync.emit(SlidingSyncEvent.Lifecycle, SlidingSyncState.RequestFinished, null, new MatrixError({
+                errcode: "M_UNKNOWN_TOKEN",
+                message: "Oh no your access token is no longer valid",
+            }));
+            expect(sdk.getSyncState()).toEqual(SyncState.Error);
+            expect(mockSlidingSync.stop).toBeCalled();
+        });
+    });
+
+    describe("opts", () => {
+        afterEach(teardownClient);
+        it("can resolveProfilesToInvites", async () => {
+            await setupClient({
+                resolveInvitesToProfiles: true,
+            });
+            const roomId = "!resolveProfilesToInvites:localhost";
+            const invitee = "@invitee:localhost";
+            const inviteeProfile = {
+                avatar_url: "mxc://foobar",
+                displayname: "The Invitee",
+            };
+            httpBackend.when("GET", "/profile").respond(200, inviteeProfile);
+            mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomId, {
+                initial: true,
+                name: "Room with Invite",
+                required_state: [],
+                timeline: [
+                    mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                    mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                    mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                    mkOwnStateEvent(EventType.RoomMember, { membership: "invite" }, invitee),
+                ],
+            });
+            await httpBackend.flush("/profile", 1, 1000);
+            const room = client.getRoom(roomId);
+            expect(room).toBeDefined();
+            const inviteeMember = room.getMember(invitee);
+            expect(inviteeMember).toBeDefined();
+            expect(inviteeMember.getMxcAvatarUrl()).toEqual(inviteeProfile.avatar_url);
+            expect(inviteeMember.name).toEqual(inviteeProfile.displayname);
+        });
+    });
+
+    describe("ExtensionE2EE", () => {
+        let ext: Extension;
+        beforeAll(async () => {
+            await setupClient({
+                withCrypto: true,
+            });
+            const hasSynced = sdk.sync();
+            await httpBackend.flushAllExpected();
+            await hasSynced;
+            ext = findExtension("e2ee");
+        });
+        afterAll(async () => {
+            // needed else we do some async operations in the background which can cause Jest to whine:
+            // "Cannot log after tests are done. Did you forget to wait for something async in your test?"
+            // Attempted to log "Saving device tracking data null"."
+            client.crypto.stop();
+        });
+        it("gets enabled on the initial request only", () => {
+            expect(ext.onRequest(true)).toEqual({
+                enabled: true,
+            });
+            expect(ext.onRequest(false)).toEqual(undefined);
+        });
+        it("can update device lists", () => {
+            ext.onResponse({
+                device_lists: {
+                    changed: ["@alice:localhost"],
+                    left: ["@bob:localhost"],
+                },
+            });
+            // TODO: more assertions?
+        });
+        it("can update OTK counts", () => {
+            client.crypto.updateOneTimeKeyCount = jest.fn();
+            ext.onResponse({
+                device_one_time_keys_count: {
+                    signed_curve25519: 42,
+                },
+            });
+            expect(client.crypto.updateOneTimeKeyCount).toHaveBeenCalledWith(42);
+            ext.onResponse({
+                device_one_time_keys_count: {
+                    not_signed_curve25519: 42,
+                    // missing field -> default to 0
+                },
+            });
+            expect(client.crypto.updateOneTimeKeyCount).toHaveBeenCalledWith(0);
+        });
+        it("can update fallback keys", () => {
+            ext.onResponse({
+                device_unused_fallback_key_types: ["signed_curve25519"],
+            });
+            expect(client.crypto.getNeedsNewFallback()).toEqual(false);
+            ext.onResponse({
+                device_unused_fallback_key_types: ["not_signed_curve25519"],
+            });
+            expect(client.crypto.getNeedsNewFallback()).toEqual(true);
+        });
+    });
+    describe("ExtensionAccountData", () => {
+        let ext: Extension;
+        beforeAll(async () => {
+            await setupClient();
+            const hasSynced = sdk.sync();
+            await httpBackend.flushAllExpected();
+            await hasSynced;
+            ext = findExtension("account_data");
+        });
+        it("gets enabled on the initial request only", () => {
+            expect(ext.onRequest(true)).toEqual({
+                enabled: true,
+            });
+            expect(ext.onRequest(false)).toEqual(undefined);
+        });
+        it("processes global account data", async () => {
+            const globalType = "global_test";
+            const globalContent = {
+                info: "here",
+            };
+            let globalData = client.getAccountData(globalType);
+            expect(globalData).toBeUndefined();
+            ext.onResponse({
+                global: [
+                    {
+                        type: globalType,
+                        content: globalContent,
+                    },
+                ],
+            });
+            globalData = client.getAccountData(globalType);
+            expect(globalData).toBeDefined();
+            expect(globalData.getContent()).toEqual(globalContent);
+        });
+        it("processes rooms account data", async () => {
+            const roomId = "!room:id";
+            mockSlidingSync.emit(SlidingSyncEvent.RoomData, roomId, {
+                name: "Room with account data",
+                required_state: [],
+                timeline: [
+                    mkOwnStateEvent(EventType.RoomCreate, { creator: selfUserId }, ""),
+                    mkOwnStateEvent(EventType.RoomMember, { membership: "join" }, selfUserId),
+                    mkOwnStateEvent(EventType.RoomPowerLevels, { users: { [selfUserId]: 100 } }, ""),
+                    mkOwnEvent(EventType.RoomMessage, { body: "hello" }),
+
+                ],
+                initial: true,
+            });
+            const roomContent = {
+                foo: "bar",
+            };
+            const roomType = "test";
+            ext.onResponse({
+                rooms: {
+                    [roomId]: [
+                        {
+                            type: roomType,
+                            content: roomContent,
+                        },
+                    ],
+                },
+            });
+            const room = client.getRoom(roomId);
+            expect(room).toBeDefined();
+            const event = room.getAccountData(roomType);
+            expect(event).toBeDefined();
+            expect(event.getContent()).toEqual(roomContent);
+        });
+        it("doesn't crash for unknown room account data", async () => {
+            const unknownRoomId = "!unknown:id";
+            const roomType = "tester";
+            ext.onResponse({
+                rooms: {
+                    [unknownRoomId]: [
+                        {
+                            type: roomType,
+                            content: {
+                                foo: "Bar",
+                            },
+                        },
+                    ],
+                },
+            });
+            const room = client.getRoom(unknownRoomId);
+            expect(room).toBeNull();
+            expect(client.getAccountData(roomType)).toBeUndefined();
+        });
+        it("can update push rules via account data", async () => {
+            const roomId = "!foo:bar";
+            const pushRulesContent: IPushRules = {
+                global: {
+                    [PushRuleKind.RoomSpecific]: [{
+                        enabled: true,
+                        default: true,
+                        pattern: "monkey",
+                        actions: [
+                            {
+                                set_tweak: TweakName.Sound,
+                                value: "default",
+                            },
+                        ],
+                        rule_id: roomId,
+                    }],
+                },
+            };
+            let pushRule = client.getRoomPushRule("global", roomId);
+            expect(pushRule).toBeUndefined();
+            ext.onResponse({
+                global: [
+                    {
+                        type: EventType.PushRules,
+                        content: pushRulesContent,
+                    },
+                ],
+            });
+            pushRule = client.getRoomPushRule("global", roomId);
+            expect(pushRule).toEqual(pushRulesContent.global[PushRuleKind.RoomSpecific][0]);
+        });
+    });
+    describe("ExtensionToDevice", () => {
+        let ext: Extension;
+        beforeAll(async () => {
+            await setupClient();
+            const hasSynced = sdk.sync();
+            await httpBackend.flushAllExpected();
+            await hasSynced;
+            ext = findExtension("to_device");
+        });
+        it("gets enabled with a limit on the initial request only", () => {
+            const reqJson: any = ext.onRequest(true);
+            expect(reqJson.enabled).toEqual(true);
+            expect(reqJson.limit).toBeGreaterThan(0);
+            expect(reqJson.since).toBeUndefined();
+        });
+        it("updates the since value", async () => {
+            ext.onResponse({
+                next_batch: "12345",
+                events: [],
+            });
+            expect(ext.onRequest(false)).toEqual({
+                since: "12345",
+            });
+        });
+        it("can handle missing fields", async () => {
+            ext.onResponse({
+                next_batch: "23456",
+                // no events array
+            });
+        });
+        it("emits to-device events on the client", async () => {
+            const toDeviceType = "custom_test";
+            const toDeviceContent = {
+                foo: "bar",
+            };
+            let called = false;
+            client.once(ClientEvent.ToDeviceEvent, (ev) => {
+                expect(ev.getContent()).toEqual(toDeviceContent);
+                expect(ev.getType()).toEqual(toDeviceType);
+                called = true;
+            });
+            ext.onResponse({
+                next_batch: "34567",
+                events: [
+                    {
+                        type: toDeviceType,
+                        content: toDeviceContent,
+                    },
+                ],
+            });
+            expect(called).toBe(true);
+        });
+        it("can cancel key verification requests", async () => {
+            const seen: Record<string, boolean> = {};
+            client.on(ClientEvent.ToDeviceEvent, (ev) => {
+                const evType = ev.getType();
+                expect(seen[evType]).toBeFalsy();
+                seen[evType] = true;
+                if (evType === "m.key.verification.start" || evType === "m.key.verification.request") {
+                    expect(ev.isCancelled()).toEqual(true);
+                } else {
+                    expect(ev.isCancelled()).toEqual(false);
+                }
+            });
+            ext.onResponse({
+                next_batch: "45678",
+                events: [
+                    // someone tries to verify keys
+                    {
+                        type: "m.key.verification.start",
+                        content: {
+                            transaction_id: "a",
+                        },
+                    },
+                    {
+                        type: "m.key.verification.request",
+                        content: {
+                            transaction_id: "a",
+                        },
+                    },
+                    // then gives up
+                    {
+                        type: "m.key.verification.cancel",
+                        content: {
+                            transaction_id: "a",
+                        },
+                    },
+                ],
+            });
+        });
+    });
+});
@@ -20,6 +20,7 @@ import * as utils from "../src/utils";

 // try to load the olm library.
 try {
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
    global.Olm = require('@matrix-org/olm');
    logger.log('loaded libolm');
 } catch (e) {
@@ -28,6 +29,7 @@ try {

 // also try to set node crypto
 try {
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
    const crypto = require('crypto');
    utils.setCrypto(crypto);
 } catch (err) {
@@ -24,5 +24,5 @@ limitations under the License.
 * expect(beaconLivenessEmits.length).toBe(1);
 * ```
 */
-export const filterEmitCallsByEventType = (eventType: string, spy: jest.SpyInstance<any, unknown[]>) =>
+export const filterEmitCallsByEventType = (eventType: string, spy: jest.SpyInstance<any, any[]>) =>
    spy.mock.calls.filter((args) => args[0] === eventType);
@@ -129,12 +129,27 @@ export function mkEvent(opts: IEventOpts & { event?: boolean }, client?: MatrixC
    return opts.event ? new MatrixEvent(event) : event;
 }

+type GeneratedMetadata = {
+    event_id: string;
+    txn_id: string;
+    origin_server_ts: number;
+};
+
+export function mkEventCustom<T>(base: T): T & GeneratedMetadata {
+    return {
+        event_id: "$" + testEventIndex++ + "-" + Math.random() + "-" + Math.random(),
+        txn_id: "~" + Math.random(),
+        origin_server_ts: Date.now(),
+        ...base,
+    };
+}
+
 interface IPresenceOpts {
    user?: string;
    sender?: string;
-    url: string;
-    name: string;
-    ago: number;
+    url?: string;
+    name?: string;
+    ago?: number;
    presence?: string;
    event?: boolean;
 }
@@ -208,6 +223,18 @@ export function mkMembership(opts: IMembershipOpts & { event?: boolean }): Parti
    return mkEvent(eventOpts);
 }

+export function mkMembershipCustom<T>(
+    base: T & { membership: string, sender: string, content?: IContent },
+): T & { type: EventType, sender: string, state_key: string, content: IContent } & GeneratedMetadata {
+    const content = base.content || {};
+    return mkEventCustom({
+        ...base,
+        content: { ...content, membership: base.membership },
+        type: EventType.RoomMember,
+        state_key: base.sender,
+    });
+}
+
 interface IMessageOpts {
    room?: string;
    user: string;
@@ -1,6 +1,6 @@
 /*
 Copyright 2018 New Vector Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -17,19 +17,20 @@ limitations under the License.

 import MockHttpBackend from "matrix-mock-request";

-import * as sdk from "../../src";
+import { request } from "../../src/matrix";
 import { AutoDiscovery } from "../../src/autodiscovery";

 describe("AutoDiscovery", function() {
-    let httpBackend = null;
-
-    beforeEach(function() {
-        httpBackend = new MockHttpBackend();
-        sdk.request(httpBackend.requestFn);
-    });
+    const getHttpBackend = (): MockHttpBackend => {
+        const httpBackend = new MockHttpBackend();
+        request(httpBackend.requestFn);
+        return httpBackend;
+    };

    it("should throw an error when no domain is specified", function() {
+        getHttpBackend();
        return Promise.all([
+            // @ts-ignore testing no args
            AutoDiscovery.findClientConfig(/* no args */).then(() => {
                throw new Error("Expected a failure, not success with no args");
            }, () => {
@@ -42,13 +43,13 @@ describe("AutoDiscovery", function() {
                return true;
            }),

-            AutoDiscovery.findClientConfig(null).then(() => {
+            AutoDiscovery.findClientConfig(null as any).then(() => {
                throw new Error("Expected a failure, not success with null");
            }, () => {
                return true;
            }),

-            AutoDiscovery.findClientConfig(true).then(() => {
+            AutoDiscovery.findClientConfig(true as any).then(() => {
                throw new Error("Expected a failure, not success with a non-string");
            }, () => {
                return true;
@@ -57,6 +58,7 @@ describe("AutoDiscovery", function() {
    });

    it("should return PROMPT when .well-known 404s", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(404, {});
        return Promise.all([
            httpBackend.flushAllExpected(),
@@ -80,6 +82,7 @@ describe("AutoDiscovery", function() {
    });

    it("should return FAIL_PROMPT when .well-known returns a 500 error", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(500, {});
        return Promise.all([
            httpBackend.flushAllExpected(),
@@ -103,6 +106,7 @@ describe("AutoDiscovery", function() {
    });

    it("should return FAIL_PROMPT when .well-known returns a 400 error", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(400, {});
        return Promise.all([
            httpBackend.flushAllExpected(),
@@ -126,6 +130,7 @@ describe("AutoDiscovery", function() {
    });

    it("should return FAIL_PROMPT when .well-known returns an empty body", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, "");
        return Promise.all([
            httpBackend.flushAllExpected(),
@@ -148,31 +153,32 @@ describe("AutoDiscovery", function() {
        ]);
    });

-    it("should return FAIL_PROMPT when .well-known returns not-JSON", function() {
-        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, "abc");
+    it("should return FAIL_PROMPT when .well-known returns not-JSON", async () => {
+        const httpBackend = getHttpBackend();
+        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, "abc", true);
+        const expected = {
+            "m.homeserver": {
+                state: "FAIL_PROMPT",
+                error: AutoDiscovery.ERROR_INVALID,
+                base_url: null,
+            },
+            "m.identity_server": {
+                state: "PROMPT",
+                error: null,
+                base_url: null,
+            },
+        };
        return Promise.all([
            httpBackend.flushAllExpected(),
-            AutoDiscovery.findClientConfig("example.org").then((conf) => {
-                const expected = {
-                    "m.homeserver": {
-                        state: "FAIL_PROMPT",
-                        error: AutoDiscovery.ERROR_INVALID,
-                        base_url: null,
-                    },
-                    "m.identity_server": {
-                        state: "PROMPT",
-                        error: null,
-                        base_url: null,
-                    },
-                };
-
-                expect(conf).toEqual(expected);
-            }),
+            AutoDiscovery.findClientConfig("example.org").then(
+                expect(expected).toEqual,
+            ),
        ]);
    });

    it("should return FAIL_PROMPT when .well-known does not have a base_url for " +
        "m.homeserver (empty string)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
            "m.homeserver": {
                base_url: "",
@@ -201,6 +207,7 @@ describe("AutoDiscovery", function() {

    it("should return FAIL_PROMPT when .well-known does not have a base_url for " +
        "m.homeserver (no property)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
            "m.homeserver": {},
        });
@@ -227,6 +234,7 @@ describe("AutoDiscovery", function() {

    it("should return FAIL_ERROR when .well-known has an invalid base_url for " +
        "m.homeserver (disallowed scheme)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
            "m.homeserver": {
                base_url: "mxc://example.org",
@@ -255,6 +263,7 @@ describe("AutoDiscovery", function() {

    it("should return FAIL_ERROR when .well-known has an invalid base_url for " +
        "m.homeserver (verification failure: 404)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").respond(404, {});
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
            "m.homeserver": {
@@ -284,6 +293,7 @@ describe("AutoDiscovery", function() {

    it("should return FAIL_ERROR when .well-known has an invalid base_url for " +
        "m.homeserver (verification failure: 500)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").respond(500, {});
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
            "m.homeserver": {
@@ -313,6 +323,7 @@ describe("AutoDiscovery", function() {

    it("should return FAIL_ERROR when .well-known has an invalid base_url for " +
        "m.homeserver (verification failure: 200 but wrong content)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
            not_matrix_versions: ["r0.0.1"],
        });
@@ -344,8 +355,9 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS when .well-known has a verifiably accurate base_url for " +
        "m.homeserver", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri).toEqual("https://example.org/_matrix/client/versions");
+            expect(req.path).toEqual("https://example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
        });
@@ -376,8 +388,9 @@ describe("AutoDiscovery", function() {
    });

    it("should return SUCCESS with the right homeserver URL", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
@@ -411,8 +424,9 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS / FAIL_PROMPT when the identity server configuration " +
        "is wrong (missing base_url)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
@@ -451,8 +465,9 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS / FAIL_PROMPT when the identity server configuration " +
        "is wrong (empty base_url)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
@@ -491,8 +506,9 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS / FAIL_PROMPT when the identity server configuration " +
        "is wrong (validation error: 404)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
@@ -532,8 +548,9 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS / FAIL_PROMPT when the identity server configuration " +
        "is wrong (validation error: 500)", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
@@ -573,14 +590,15 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS when the identity server configuration is " +
        "verifiably accurate", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
        });
        httpBackend.when("GET", "/_matrix/identity/api/v1").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://identity.example.org/_matrix/identity/api/v1");
        }).respond(200, {});
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
@@ -615,14 +633,15 @@ describe("AutoDiscovery", function() {

    it("should return SUCCESS and preserve non-standard keys from the " +
        ".well-known response", function() {
+        const httpBackend = getHttpBackend();
        httpBackend.when("GET", "/_matrix/client/versions").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://chat.example.org/_matrix/client/versions");
        }).respond(200, {
            versions: ["r0.0.1"],
        });
        httpBackend.when("GET", "/_matrix/identity/api/v1").check((req) => {
-            expect(req.opts.uri)
+            expect(req.path)
                .toEqual("https://identity.example.org/_matrix/identity/api/v1");
        }).respond(200, {});
        httpBackend.when("GET", "/.well-known/matrix/client").respond(200, {
@@ -19,41 +19,41 @@ describe("ContentRepo", function() {
        });

        it("should return a download URL if no width/height/resize are specified",
-        function() {
-            const mxcUri = "mxc://server.name/resourceid";
-            expect(getHttpUriForMxc(baseUrl, mxcUri)).toEqual(
-                baseUrl + "/_matrix/media/r0/download/server.name/resourceid",
-            );
-        });
+            function() {
+                const mxcUri = "mxc://server.name/resourceid";
+                expect(getHttpUriForMxc(baseUrl, mxcUri)).toEqual(
+                    baseUrl + "/_matrix/media/r0/download/server.name/resourceid",
+                );
+            });

        it("should return the empty string for null input", function() {
-            expect(getHttpUriForMxc(null)).toEqual("");
+            expect(getHttpUriForMxc(null as any, '')).toEqual("");
        });

        it("should return a thumbnail URL if a width/height/resize is specified",
-        function() {
-            const mxcUri = "mxc://server.name/resourceid";
-            expect(getHttpUriForMxc(baseUrl, mxcUri, 32, 64, "crop")).toEqual(
-                baseUrl + "/_matrix/media/r0/thumbnail/server.name/resourceid" +
+            function() {
+                const mxcUri = "mxc://server.name/resourceid";
+                expect(getHttpUriForMxc(baseUrl, mxcUri, 32, 64, "crop")).toEqual(
+                    baseUrl + "/_matrix/media/r0/thumbnail/server.name/resourceid" +
                "?width=32&height=64&method=crop",
-            );
-        });
+                );
+            });

        it("should put fragments from mxc:// URIs after any query parameters",
-        function() {
-            const mxcUri = "mxc://server.name/resourceid#automade";
-            expect(getHttpUriForMxc(baseUrl, mxcUri, 32)).toEqual(
-                baseUrl + "/_matrix/media/r0/thumbnail/server.name/resourceid" +
+            function() {
+                const mxcUri = "mxc://server.name/resourceid#automade";
+                expect(getHttpUriForMxc(baseUrl, mxcUri, 32)).toEqual(
+                    baseUrl + "/_matrix/media/r0/thumbnail/server.name/resourceid" +
                "?width=32#automade",
-            );
-        });
+                );
+            });

        it("should put fragments from mxc:// URIs at the end of the HTTP URI",
-        function() {
-            const mxcUri = "mxc://server.name/resourceid#automade";
-            expect(getHttpUriForMxc(baseUrl, mxcUri)).toEqual(
-                baseUrl + "/_matrix/media/r0/download/server.name/resourceid#automade",
-            );
-        });
+            function() {
+                const mxcUri = "mxc://server.name/resourceid#automade";
+                expect(getHttpUriForMxc(baseUrl, mxcUri)).toEqual(
+                    baseUrl + "/_matrix/media/r0/download/server.name/resourceid#automade",
+                );
+            });
    });
 });
@@ -2,6 +2,7 @@ import '../olm-loader';
 // eslint-disable-next-line no-restricted-imports
 import { EventEmitter } from "events";

+import { MatrixClient } from "../../src/client";
 import { Crypto } from "../../src/crypto";
 import { MemoryCryptoStore } from "../../src/crypto/store/memory-crypto-store";
 import { MockStorageApi } from "../MockStorageApi";
@@ -14,6 +15,7 @@ import { CRYPTO_ENABLED } from "../../src/client";
 import { DeviceInfo } from "../../src/crypto/deviceinfo";
 import { logger } from '../../src/logger';
 import { MemoryStore } from "../../src";
+import { IStore } from '../../src/store';

 const Olm = global.Olm;

@@ -25,7 +27,7 @@ function awaitEvent(emitter, event) {
    });
 }

-async function keyshareEventForEvent(client, event, index) {
+async function keyshareEventForEvent(client, event, index): Promise<MatrixEvent> {
    const roomId = event.getRoomId();
    const eventContent = event.getWireContent();
    const key = await client.crypto.olmDevice.getInboundGroupSessionKey(
@@ -50,6 +52,7 @@ async function keyshareEventForEvent(client, event, index) {
        },
    });
    // make onRoomKeyEvent think this was an encrypted event
+    // @ts-ignore private property
    ksEvent.senderCurve25519Key = "akey";
    return ksEvent;
 }
@@ -63,6 +66,10 @@ describe("Crypto", function() {
        return Olm.init();
    });

+    afterEach(() => {
+        jest.useRealTimers();
+    });
+
    it("Crypto exposes the correct olm library version", function() {
        expect(Crypto.getOlmVersion()[0]).toEqual(3);
    });
@@ -79,7 +86,7 @@ describe("Crypto", function() {
                getId: () => "$event_id",
                getSenderKey: () => null,
                getWireContent: () => {return {};},
-            };
+            } as unknown as MatrixEvent;

            let encryptionInfo = client.getEventEncryptionInfo(event);
            expect(encryptionInfo.encrypted).toBeFalsy();
@@ -152,14 +159,17 @@ describe("Crypto", function() {
        let fakeEmitter;

        beforeEach(async function() {
-            const mockStorage = new MockStorageApi();
-            const clientStore = new MemoryStore({ localStorage: mockStorage });
-            const cryptoStore = new MemoryCryptoStore(mockStorage);
+            const mockStorage = new MockStorageApi() as unknown as Storage;
+            const clientStore = new MemoryStore({ localStorage: mockStorage }) as unknown as IStore;
+            const cryptoStore = new MemoryCryptoStore();

            cryptoStore.storeEndToEndDeviceData({
                devices: {
                    '@bob:home.server': {
                        'BOBDEVICE': {
+                            algorithms: [],
+                            verified: 1,
+                            known: false,
                            keys: {
                                'curve25519:BOBDEVICE': 'this is a key',
                            },
@@ -167,7 +177,7 @@ describe("Crypto", function() {
                    },
                },
                trackingStatus: {},
-            });
+            }, {});

            mockBaseApis = {
                sendToDevice: jest.fn(),
@@ -185,6 +195,7 @@ describe("Crypto", function() {
                clientStore,
                cryptoStore,
                mockRoomList,
+                [],
            );
            crypto.registerEventHandlers(fakeEmitter);
            await crypto.init();
@@ -195,7 +206,7 @@ describe("Crypto", function() {
        });

        it("restarts wedged Olm sessions", async function() {
-            const prom = new Promise((resolve) => {
+            const prom = new Promise<void>((resolve) => {
                mockBaseApis.claimOneTimeKeys = function() {
                    resolve();
                    return otkResponse;
@@ -220,8 +231,8 @@ describe("Crypto", function() {
    });

    describe('Key requests', function() {
-        let aliceClient;
-        let bobClient;
+        let aliceClient: MatrixClient;
+        let bobClient: MatrixClient;

        beforeEach(async function() {
            aliceClient = (new TestClient(
@@ -276,8 +287,12 @@ describe("Crypto", function() {
                // alice encrypts each event, and then bob tries to decrypt
                // them without any keys, so that they'll be in pending
                await aliceClient.crypto.encryptEvent(event, aliceRoom);
+                // remove keys from the event
+                // @ts-ignore private properties
                event.clearEvent = undefined;
+                // @ts-ignore private properties
                event.senderCurve25519Key = null;
+                // @ts-ignore private properties
                event.claimedEd25519Key = null;
                try {
                    await bobClient.crypto.decryptEvent(event);
@@ -291,7 +306,7 @@ describe("Crypto", function() {
                roomId, olmlib.MEGOLM_ALGORITHM,
            );

-            let eventPromise = Promise.all(events.map((ev) => {
+            const decryptEventsPromise = Promise.all(events.map((ev) => {
                return awaitEvent(ev, "Event.decrypted");
            }));

@@ -300,11 +315,11 @@ describe("Crypto", function() {
            // can
            let ksEvent = await keyshareEventForEvent(aliceClient, events[1], 1);
            await bobDecryptor.onRoomKeyEvent(ksEvent);
-            await eventPromise;
+            await decryptEventsPromise;
            expect(events[0].getContent().msgtype).toBe("m.bad.encrypted");
            expect(events[1].getContent().msgtype).not.toBe("m.bad.encrypted");

-            const cryptoStore = bobClient.cryptoStore;
+            const cryptoStore = bobClient.crypto.cryptoStore;
            const eventContent = events[0].getWireContent();
            const senderKey = eventContent.sender_key;
            const sessionId = eventContent.session_id;
@@ -320,10 +335,10 @@ describe("Crypto", function() {

            // keyshare the session key starting at the first message, so
            // that it can now be decrypted
-            eventPromise = awaitEvent(events[0], "Event.decrypted");
+            const decryptEventPromise = awaitEvent(events[0], "Event.decrypted");
            ksEvent = await keyshareEventForEvent(aliceClient, events[0], 0);
            await bobDecryptor.onRoomKeyEvent(ksEvent);
-            await eventPromise;
+            await decryptEventPromise;
            expect(events[0].getContent().msgtype).not.toBe("m.bad.encrypted");
            await sleep(1);
            // the room key request should be gone since we've now decrypted everything
@@ -354,8 +369,12 @@ describe("Crypto", function() {
            // alice encrypts each event, and then bob tries to decrypt
            // them without any keys, so that they'll be in pending
            await aliceClient.crypto.encryptEvent(event, aliceRoom);
+            // remove keys from the event
+            // @ts-ignore private property
            event.clearEvent = undefined;
+            // @ts-ignore private property
            event.senderCurve25519Key = null;
+            // @ts-ignore private property
            event.claimedEd25519Key = null;
            try {
                await bobClient.crypto.decryptEvent(event);
@@ -370,9 +389,9 @@ describe("Crypto", function() {

            const ksEvent = await keyshareEventForEvent(aliceClient, event, 1);
            ksEvent.getContent().sender_key = undefined; // test
-            bobClient.crypto.addInboundGroupSession = jest.fn();
+            bobClient.crypto.olmDevice.addInboundGroupSession = jest.fn();
            await bobDecryptor.onRoomKeyEvent(ksEvent);
-            expect(bobClient.crypto.addInboundGroupSession).not.toHaveBeenCalled();
+            expect(bobClient.crypto.olmDevice.addInboundGroupSession).not.toHaveBeenCalled();
        });

        it("creates a new keyshare request if we request a keyshare", async function() {
@@ -388,7 +407,7 @@ describe("Crypto", function() {
                },
            });
            await aliceClient.cancelAndResendEventRoomKeyRequest(event);
-            const cryptoStore = aliceClient.cryptoStore;
+            const cryptoStore = aliceClient.crypto.cryptoStore;
            const roomKeyRequestBody = {
                algorithm: olmlib.MEGOLM_ALGORITHM,
                room_id: "!someroom",
@@ -412,7 +431,8 @@ describe("Crypto", function() {
                },
            });
            // replace Alice's sendToDevice function with a mock
-            aliceClient.sendToDevice = jest.fn().mockResolvedValue(undefined);
+            const aliceSendToDevice = jest.fn().mockResolvedValue(undefined);
+            aliceClient.sendToDevice = aliceSendToDevice;
            aliceClient.startClient();

            // make a room key request, and record the transaction ID for the
@@ -421,11 +441,12 @@ describe("Crypto", function() {
            // key requests get queued until the sync has finished, but we don't
            // let the client set up enough for that to happen, so gut-wrench a bit
            // to force it to send now.
+            // @ts-ignore
            aliceClient.crypto.outgoingRoomKeyRequestManager.sendQueuedRequests();
            jest.runAllTimers();
            await Promise.resolve();
-            expect(aliceClient.sendToDevice).toBeCalledTimes(1);
-            const txnId = aliceClient.sendToDevice.mock.calls[0][2];
+            expect(aliceSendToDevice).toBeCalledTimes(1);
+            const txnId = aliceSendToDevice.mock.calls[0][2];

            // give the room key request manager time to update the state
            // of the request
@@ -438,8 +459,8 @@ describe("Crypto", function() {
            // cancelAndResend will call sendToDevice twice:
            // the first call to sendToDevice will be the cancellation
            // the second call to sendToDevice will be the key request
-            expect(aliceClient.sendToDevice).toBeCalledTimes(3);
-            expect(aliceClient.sendToDevice.mock.calls[2][2]).not.toBe(txnId);
+            expect(aliceSendToDevice).toBeCalledTimes(3);
+            expect(aliceSendToDevice.mock.calls[2][2]).not.toBe(txnId);
        });
    });

@@ -449,12 +470,12 @@ describe("Crypto", function() {
            jest.setTimeout(10000);
            const client = (new TestClient("@a:example.com", "dev")).client;
            await client.initCrypto();
-            client.crypto.getSecretStorageKey = async () => null;
+            client.crypto.getSecretStorageKey = jest.fn().mockResolvedValue(null);
            client.crypto.isCrossSigningReady = async () => false;
-            client.crypto.baseApis.uploadDeviceSigningKeys = () => null;
-            client.crypto.baseApis.setAccountData = () => null;
-            client.crypto.baseApis.uploadKeySignatures = () => null;
-            client.crypto.baseApis.http.authedRequest = () => null;
+            client.crypto.baseApis.uploadDeviceSigningKeys = jest.fn().mockResolvedValue(null);
+            client.crypto.baseApis.setAccountData = jest.fn().mockResolvedValue(null);
+            client.crypto.baseApis.uploadKeySignatures = jest.fn();
+            client.crypto.baseApis.http.authedRequest = jest.fn();
            const createSecretStorageKey = async () => {
                return {
                    keyInfo: undefined, // Returning undefined here used to cause a crash
@@ -467,4 +488,105 @@ describe("Crypto", function() {
            client.stopClient();
        });
    });
+
+    describe("encryptAndSendToDevices", () => {
+        let client: TestClient;
+        let ensureOlmSessionsForDevices: jest.SpiedFunction<typeof olmlib.ensureOlmSessionsForDevices>;
+        let encryptMessageForDevice: jest.SpiedFunction<typeof olmlib.encryptMessageForDevice>;
+        const payload = { hello: "world" };
+        let encryptedPayload: object;
+
+        beforeEach(async () => {
+            ensureOlmSessionsForDevices = jest.spyOn(olmlib, "ensureOlmSessionsForDevices");
+            ensureOlmSessionsForDevices.mockResolvedValue({});
+            encryptMessageForDevice = jest.spyOn(olmlib, "encryptMessageForDevice");
+            encryptMessageForDevice.mockImplementation(async (...[result,,,,,, payload]) => {
+                result.plaintext = JSON.stringify(payload);
+            });
+
+            client = new TestClient("@alice:example.org", "aliceweb");
+            await client.client.initCrypto();
+
+            encryptedPayload = {
+                algorithm: "m.olm.v1.curve25519-aes-sha2",
+                sender_key: client.client.crypto.olmDevice.deviceCurve25519Key,
+                ciphertext: { plaintext: JSON.stringify(payload) },
+            };
+        });
+
+        afterEach(async () => {
+            ensureOlmSessionsForDevices.mockRestore();
+            encryptMessageForDevice.mockRestore();
+            await client.stop();
+        });
+
+        it("encrypts and sends to devices", async () => {
+            client.httpBackend
+                .when("PUT", "/sendToDevice/m.room.encrypted", {
+                    messages: {
+                        "@bob:example.org": {
+                            bobweb: encryptedPayload,
+                            bobmobile: encryptedPayload,
+                        },
+                        "@carol:example.org": {
+                            caroldesktop: encryptedPayload,
+                        },
+                    },
+                })
+                .respond(200, {});
+
+            await Promise.all([
+                client.client.encryptAndSendToDevices(
+                    [
+                        { userId: "@bob:example.org", deviceInfo: new DeviceInfo("bobweb") },
+                        { userId: "@bob:example.org", deviceInfo: new DeviceInfo("bobmobile") },
+                        { userId: "@carol:example.org", deviceInfo: new DeviceInfo("caroldesktop") },
+                    ],
+                    payload,
+                ),
+                client.httpBackend.flushAllExpected(),
+            ]);
+        });
+
+        it("sends nothing to devices that couldn't be encrypted to", async () => {
+            encryptMessageForDevice.mockImplementation(async (...[result,,,, userId, device, payload]) => {
+                // Refuse to encrypt to Carol's desktop device
+                if (userId === "@carol:example.org" && device.deviceId === "caroldesktop") return;
+                result.plaintext = JSON.stringify(payload);
+            });
+
+            client.httpBackend
+                .when("PUT", "/sendToDevice/m.room.encrypted", {
+                    // Carol is nowhere to be seen
+                    messages: { "@bob:example.org": { bobweb: encryptedPayload } },
+                })
+                .respond(200, {});
+
+            await Promise.all([
+                client.client.encryptAndSendToDevices(
+                    [
+                        { userId: "@bob:example.org", deviceInfo: new DeviceInfo("bobweb") },
+                        { userId: "@carol:example.org", deviceInfo: new DeviceInfo("caroldesktop") },
+                    ],
+                    payload,
+                ),
+                client.httpBackend.flushAllExpected(),
+            ]);
+        });
+
+        it("no-ops if no devices can be encrypted to", async () => {
+            // Refuse to encrypt to anybody
+            encryptMessageForDevice.mockResolvedValue(undefined);
+
+            // Get the room keys version request out of the way
+            client.httpBackend.when("GET", "/room_keys/version").respond(404, {});
+            await client.httpBackend.flush("/room_keys/version", 1);
+
+            await client.client.encryptAndSendToDevices(
+                [{ userId: "@bob:example.org", deviceInfo: new DeviceInfo("bobweb") }],
+                payload,
+            );
+            client.httpBackend.verifyNoOutstandingRequests();
+        });
+    });
 });
@@ -1,18 +1,39 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { mocked, MockedObject } from 'jest-mock';
+
 import '../../../olm-loader';
 import * as algorithms from "../../../../src/crypto/algorithms";
 import { MemoryCryptoStore } from "../../../../src/crypto/store/memory-crypto-store";
-import { MockStorageApi } from "../../../MockStorageApi";
 import * as testUtils from "../../../test-utils/test-utils";
 import { OlmDevice } from "../../../../src/crypto/OlmDevice";
-import { Crypto } from "../../../../src/crypto";
+import { Crypto, IncomingRoomKeyRequest } from "../../../../src/crypto";
 import { logger } from "../../../../src/logger";
 import { MatrixEvent } from "../../../../src/models/event";
 import { TestClient } from "../../../TestClient";
 import { Room } from "../../../../src/models/room";
 import * as olmlib from "../../../../src/crypto/olmlib";
+import { TypedEventEmitter } from '../../../../src/models/typed-event-emitter';
+import { ClientEvent, MatrixClient, RoomMember } from '../../../../src';
+import { DeviceInfo, IDevice } from '../../../../src/crypto/deviceinfo';
+import { DeviceTrustLevel } from '../../../../src/crypto/CrossSigning';

-const MegolmDecryption = algorithms.DECRYPTION_CLASSES['m.megolm.v1.aes-sha2'];
-const MegolmEncryption = algorithms.ENCRYPTION_CLASSES['m.megolm.v1.aes-sha2'];
+const MegolmDecryption = algorithms.DECRYPTION_CLASSES.get('m.megolm.v1.aes-sha2');
+const MegolmEncryption = algorithms.ENCRYPTION_CLASSES.get('m.megolm.v1.aes-sha2');

 const ROOM_ID = '!ROOM:ID';

@@ -28,17 +49,20 @@ describe("MegolmDecryption", function() {
        return Olm.init();
    });

-    let megolmDecryption;
-    let mockOlmLib;
-    let mockCrypto;
-    let mockBaseApis;
+    let megolmDecryption: algorithms.DecryptionAlgorithm;
+    let mockOlmLib: MockedObject<typeof olmlib>;
+    let mockCrypto: MockedObject<Crypto>;
+    let mockBaseApis: MockedObject<MatrixClient>;

    beforeEach(async function() {
-        mockCrypto = testUtils.mock(Crypto, 'Crypto');
-        mockBaseApis = {};
+        mockCrypto = testUtils.mock(Crypto, 'Crypto') as MockedObject<Crypto>;
+        mockBaseApis = {
+            claimOneTimeKeys: jest.fn(),
+            sendToDevice: jest.fn(),
+            queueToDevice: jest.fn(),
+        } as unknown as MockedObject<MatrixClient>;

-        const mockStorage = new MockStorageApi();
-        const cryptoStore = new MemoryCryptoStore(mockStorage);
+        const cryptoStore = new MemoryCryptoStore();

        const olmDevice = new OlmDevice(cryptoStore);

@@ -51,11 +75,15 @@ describe("MegolmDecryption", function() {
        });

        // we stub out the olm encryption bits
-        mockOlmLib = {};
-        mockOlmLib.ensureOlmSessionsForDevices = jest.fn();
-        mockOlmLib.encryptMessageForDevice =
-            jest.fn().mockResolvedValue(undefined);
+        mockOlmLib = {
+            encryptMessageForDevice: jest.fn().mockResolvedValue(undefined),
+            ensureOlmSessionsForDevices: jest.fn(),
+        } as unknown as MockedObject<typeof olmlib>;
+
+        // @ts-ignore illegal assignment that makes these tests work :/
        megolmDecryption.olmlib = mockOlmLib;
+
+        jest.clearAllMocks();
    });

    describe('receives some keys:', function() {
@@ -87,7 +115,7 @@ describe("MegolmDecryption", function() {
                decryptEvent: function() {
                    return Promise.resolve(decryptedData);
                },
-            };
+            } as unknown as Crypto;

            await event.attemptDecryption(mockCrypto).then(() => {
                megolmDecryption.onRoomKeyEvent(event);
@@ -115,10 +143,13 @@ describe("MegolmDecryption", function() {
        });

        it('can respond to a key request event', function() {
-            const keyRequest = {
+            const keyRequest: IncomingRoomKeyRequest = {
+                requestId: '123',
+                share: jest.fn(),
                userId: '@alice:foo',
                deviceId: 'alidevice',
                requestBody: {
+                    algorithm: '',
                    room_id: ROOM_ID,
                    sender_key: "SENDER_CURVE25519",
                    session_id: groupSession.session_id(),
@@ -131,23 +162,25 @@ describe("MegolmDecryption", function() {
                expect(hasKeys).toBe(true);

                // set up some pre-conditions for the share call
-                const deviceInfo = {};
+                const deviceInfo = {} as DeviceInfo;
                mockCrypto.getStoredDevice.mockReturnValue(deviceInfo);

                mockOlmLib.ensureOlmSessionsForDevices.mockResolvedValue({
                    '@alice:foo': { 'alidevice': {
                        sessionId: 'alisession',
+                        device: new DeviceInfo('alidevice'),
                    } },
                });

-                const awaitEncryptForDevice = new Promise((res, rej) => {
+                const awaitEncryptForDevice = new Promise<void>((res, rej) => {
                    mockOlmLib.encryptMessageForDevice.mockImplementation(() => {
                        res();
                        return Promise.resolve();
                    });
                });

-                mockBaseApis.sendToDevice = jest.fn();
+                mockBaseApis.sendToDevice.mockReset();
+                mockBaseApis.queueToDevice.mockReset();

                // do the share
                megolmDecryption.shareKeysWithDevice(keyRequest);
@@ -265,17 +298,18 @@ describe("MegolmDecryption", function() {
            let olmDevice;

            beforeEach(async () => {
+                // @ts-ignore assigning to readonly prop
                mockCrypto.backupManager = {
                    backupGroupSession: () => {},
                };
-                const mockStorage = new MockStorageApi();
-                const cryptoStore = new MemoryCryptoStore(mockStorage);
+                const cryptoStore = new MemoryCryptoStore();

                olmDevice = new OlmDevice(cryptoStore);
                olmDevice.verifySignature = jest.fn();
                await olmDevice.init();

-                mockBaseApis.claimOneTimeKeys = jest.fn().mockReturnValue(Promise.resolve({
+                mockBaseApis.claimOneTimeKeys.mockResolvedValue({
+                    failures: {},
                    one_time_keys: {
                        '@alice:home.server': {
                            aliceDevice: {
@@ -290,8 +324,9 @@ describe("MegolmDecryption", function() {
                            },
                        },
                    },
-                }));
-                mockBaseApis.sendToDevice = jest.fn().mockResolvedValue(undefined);
+                });
+                mockBaseApis.sendToDevice.mockResolvedValue(undefined);
+                mockBaseApis.queueToDevice.mockResolvedValue(undefined);

                aliceDeviceInfo = {
                    deviceId: 'aliceDevice',
@@ -311,18 +346,30 @@ describe("MegolmDecryption", function() {

                mockCrypto.checkDeviceTrust.mockReturnValue({
                    isVerified: () => false,
-                });
+                } as DeviceTrustLevel);

                megolmEncryption = new MegolmEncryption({
                    userId: '@user:id',
+                    deviceId: '12345',
                    crypto: mockCrypto,
                    olmDevice: olmDevice,
                    baseApis: mockBaseApis,
                    roomId: ROOM_ID,
                    config: {
+                        algorithm: 'm.megolm.v1.aes-sha2',
                        rotation_period_ms: rotationPeriodMs,
                    },
                });
+
+                // Splice the real method onto the mock object as megolm uses this method
+                // on the crypto class in order to encrypt / start sessions
+                // @ts-ignore Mock
+                mockCrypto.encryptAndSendToDevices = Crypto.prototype.encryptAndSendToDevices;
+                // @ts-ignore Mock
+                mockCrypto.olmDevice = olmDevice;
+                // @ts-ignore Mock
+                mockCrypto.baseApis = mockBaseApis;
+
                mockRoom = {
                    getEncryptionTargetMembers: jest.fn().mockReturnValue(
                        [{ userId: "@alice:home.server" }],
@@ -369,7 +416,7 @@ describe("MegolmDecryption", function() {
                expect(mockCrypto.downloadKeys).toHaveBeenCalledWith(
                    ['@alice:home.server'], false,
                );
-                expect(mockBaseApis.sendToDevice).toHaveBeenCalled();
+                expect(mockBaseApis.queueToDevice).toHaveBeenCalled();
                expect(mockBaseApis.claimOneTimeKeys).toHaveBeenCalledWith(
                    [['@alice:home.server', 'aliceDevice']], 'signed_curve25519', 2000,
                );
@@ -412,7 +459,7 @@ describe("MegolmDecryption", function() {
                    'YWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWI',
                );

-                mockBaseApis.sendToDevice.mockClear();
+                mockBaseApis.queueToDevice.mockClear();
                await megolmEncryption.reshareKeyWithDevice(
                    olmDevice.deviceCurve25519Key,
                    ct1.session_id,
@@ -420,7 +467,7 @@ describe("MegolmDecryption", function() {
                    aliceDeviceInfo,
                );

-                expect(mockBaseApis.sendToDevice).not.toHaveBeenCalled();
+                expect(mockBaseApis.queueToDevice).not.toHaveBeenCalled();
            });
        });
    });
@@ -449,33 +496,33 @@ describe("MegolmDecryption", function() {
        };
        const roomId = "!someroom";
        const room = new Room(roomId, aliceClient, "@alice:example.com", {});
+
+        const bobMember = new RoomMember(roomId, "@bob:example.com");
        room.getEncryptionTargetMembers = async function() {
-            return [{ userId: "@bob:example.com" }];
+            return [bobMember];
        };
        room.setBlacklistUnverifiedDevices(true);
        aliceClient.store.storeRoom(room);
        await aliceClient.setRoomEncryption(roomId, encryptionCfg);

-        const BOB_DEVICES = {
+        const BOB_DEVICES: Record<string, IDevice> = {
            bobdevice1: {
-                user_id: "@bob:example.com",
-                device_id: "bobdevice1",
                algorithms: [olmlib.OLM_ALGORITHM, olmlib.MEGOLM_ALGORITHM],
                keys: {
                    "ed25519:Dynabook": bobDevice1.deviceEd25519Key,
                    "curve25519:Dynabook": bobDevice1.deviceCurve25519Key,
                },
                verified: 0,
+                known: false,
            },
            bobdevice2: {
-                user_id: "@bob:example.com",
-                device_id: "bobdevice2",
                algorithms: [olmlib.OLM_ALGORITHM, olmlib.MEGOLM_ALGORITHM],
                keys: {
                    "ed25519:Dynabook": bobDevice2.deviceEd25519Key,
                    "curve25519:Dynabook": bobDevice2.deviceCurve25519Key,
                },
                verified: -1,
+                known: false,
            },
        };

@@ -486,32 +533,7 @@ describe("MegolmDecryption", function() {
            return this.getDevicesFromStore(userIds);
        };

-        let run = false;
-        aliceClient.sendToDevice = async (msgtype, contentMap) => {
-            run = true;
-            expect(msgtype).toMatch(/^(org.matrix|m).room_key.withheld$/);
-            delete contentMap["@bob:example.com"].bobdevice1.session_id;
-            delete contentMap["@bob:example.com"].bobdevice2.session_id;
-            expect(contentMap).toStrictEqual({
-                '@bob:example.com': {
-                    bobdevice1: {
-                        algorithm: "m.megolm.v1.aes-sha2",
-                        room_id: roomId,
-                        code: 'm.unverified',
-                        reason:
-                        'The sender has disabled encrypting to unverified devices.',
-                        sender_key: aliceDevice.deviceCurve25519Key,
-                    },
-                    bobdevice2: {
-                        algorithm: "m.megolm.v1.aes-sha2",
-                        room_id: roomId,
-                        code: 'm.blacklisted',
-                        reason: 'The sender has blocked you.',
-                        sender_key: aliceDevice.deviceCurve25519Key,
-                    },
-                },
-            });
-        };
+        aliceClient.sendToDevice = jest.fn().mockResolvedValue({});

        const event = new MatrixEvent({
            type: "m.room.message",
@@ -525,7 +547,30 @@ describe("MegolmDecryption", function() {
        });
        await aliceClient.crypto.encryptEvent(event, room);

-        expect(run).toBe(true);
+        expect(aliceClient.sendToDevice).toHaveBeenCalled();
+        const [msgtype, contentMap] = mocked(aliceClient.sendToDevice).mock.calls[0];
+        expect(msgtype).toMatch(/^(org.matrix|m).room_key.withheld$/);
+        delete contentMap["@bob:example.com"].bobdevice1.session_id;
+        delete contentMap["@bob:example.com"].bobdevice2.session_id;
+        expect(contentMap).toStrictEqual({
+            '@bob:example.com': {
+                bobdevice1: {
+                    algorithm: "m.megolm.v1.aes-sha2",
+                    room_id: roomId,
+                    code: 'm.unverified',
+                    reason:
+                    'The sender has disabled encrypting to unverified devices.',
+                    sender_key: aliceDevice.deviceCurve25519Key,
+                },
+                bobdevice2: {
+                    algorithm: "m.megolm.v1.aes-sha2",
+                    room_id: roomId,
+                    code: 'm.blacklisted',
+                    reason: 'The sender has blocked you.',
+                    sender_key: aliceDevice.deviceCurve25519Key,
+                },
+            },
+        });

        aliceClient.stopClient();
        bobClient1.stopClient();
@@ -557,18 +602,16 @@ describe("MegolmDecryption", function() {
        await aliceClient.setRoomEncryption(roomId, encryptionCfg);
        await bobClient.setRoomEncryption(roomId, encryptionCfg);

-        aliceRoom.getEncryptionTargetMembers = async () => {
-            return [
-                {
-                    userId: "@alice:example.com",
-                    membership: "join",
-                },
-                {
-                    userId: "@bob:example.com",
-                    membership: "join",
-                },
-            ];
-        };
+        aliceRoom.getEncryptionTargetMembers = jest.fn().mockResolvedValue([
+            {
+                userId: "@alice:example.com",
+                membership: "join",
+            },
+            {
+                userId: "@bob:example.com",
+                membership: "join",
+            },
+        ]);
        const BOB_DEVICES = {
            bobdevice: {
                user_id: "@bob:example.com",
@@ -590,30 +633,14 @@ describe("MegolmDecryption", function() {
            return this.getDevicesFromStore(userIds);
        };

-        aliceClient.claimOneTimeKeys = async () => {
+        aliceClient.claimOneTimeKeys = jest.fn().mockResolvedValue({
            // Bob has no one-time keys
-            return {
-                one_time_keys: {},
-            };
-        };
-
-        const sendPromise = new Promise((resolve, reject) => {
-            aliceClient.sendToDevice = async (msgtype, contentMap) => {
-                expect(msgtype).toMatch(/^(org.matrix|m).room_key.withheld$/);
-                expect(contentMap).toStrictEqual({
-                    '@bob:example.com': {
-                        bobdevice: {
-                            algorithm: "m.megolm.v1.aes-sha2",
-                            code: 'm.no_olm',
-                            reason: 'Unable to establish a secure channel.',
-                            sender_key: aliceDevice.deviceCurve25519Key,
-                        },
-                    },
-                });
-                resolve();
-            };
+            one_time_keys: {},
+            failures: {},
        });

+        aliceClient.sendToDevice = jest.fn().mockResolvedValue({});
+
        const event = new MatrixEvent({
            type: "m.room.message",
            sender: "@alice:example.com",
@@ -622,7 +649,21 @@ describe("MegolmDecryption", function() {
            content: {},
        });
        await aliceClient.crypto.encryptEvent(event, aliceRoom);
-        await sendPromise;
+
+        expect(aliceClient.sendToDevice).toHaveBeenCalled();
+        const [msgtype, contentMap] = mocked(aliceClient.sendToDevice).mock.calls[0];
+        expect(msgtype).toMatch(/^(org.matrix|m).room_key.withheld$/);
+        expect(contentMap).toStrictEqual({
+            '@bob:example.com': {
+                bobdevice: {
+                    algorithm: "m.megolm.v1.aes-sha2",
+                    code: 'm.no_olm',
+                    reason: 'Unable to establish a secure channel.',
+                    sender_key: aliceDevice.deviceCurve25519Key,
+                },
+            },
+        });
+
        aliceClient.stopClient();
        bobClient.stopClient();
    });
@@ -640,10 +681,13 @@ describe("MegolmDecryption", function() {
        ]);
        const bobDevice = bobClient.crypto.olmDevice;

+        const aliceEventEmitter = new TypedEventEmitter<ClientEvent.ToDeviceEvent, any>();
+        aliceClient.crypto.registerEventHandlers(aliceEventEmitter);
+
        const roomId = "!someroom";

-        aliceClient.crypto.onToDeviceEvent(new MatrixEvent({
-            type: "org.matrix.room_key.withheld",
+        aliceEventEmitter.emit(ClientEvent.ToDeviceEvent, new MatrixEvent({
+            type: "m.room_key.withheld",
            sender: "@bob:example.com",
            content: {
                algorithm: "m.megolm.v1.aes-sha2",
@@ -669,7 +713,7 @@ describe("MegolmDecryption", function() {
            },
        }))).rejects.toThrow("The sender has blocked you.");

-        aliceClient.crypto.onToDeviceEvent(new MatrixEvent({
+        aliceEventEmitter.emit(ClientEvent.ToDeviceEvent, new MatrixEvent({
            type: "m.room_key.withheld",
            sender: "@bob:example.com",
            content: {
@@ -710,15 +754,19 @@ describe("MegolmDecryption", function() {
            aliceClient.initCrypto(),
            bobClient.initCrypto(),
        ]);
-        aliceClient.crypto.downloadKeys = async () => {};
+
+        const aliceEventEmitter = new TypedEventEmitter<ClientEvent.ToDeviceEvent, any>();
+        aliceClient.crypto.registerEventHandlers(aliceEventEmitter);
+
+        aliceClient.crypto.downloadKeys = jest.fn();
        const bobDevice = bobClient.crypto.olmDevice;

        const roomId = "!someroom";

        const now = Date.now();

-        aliceClient.crypto.onToDeviceEvent(new MatrixEvent({
-            type: "org.matrix.room_key.withheld",
+        aliceEventEmitter.emit(ClientEvent.ToDeviceEvent, new MatrixEvent({
+            type: "m.room_key.withheld",
            sender: "@bob:example.com",
            content: {
                algorithm: "m.megolm.v1.aes-sha2",
@@ -749,7 +797,7 @@ describe("MegolmDecryption", function() {
            origin_server_ts: now,
        }))).rejects.toThrow("The sender was unable to establish a secure channel.");

-        aliceClient.crypto.onToDeviceEvent(new MatrixEvent({
+        aliceEventEmitter.emit(ClientEvent.ToDeviceEvent, new MatrixEvent({
            type: "m.room_key.withheld",
            sender: "@bob:example.com",
            content: {
@@ -795,15 +843,18 @@ describe("MegolmDecryption", function() {
            aliceClient.initCrypto(),
            bobClient.initCrypto(),
        ]);
+        const aliceEventEmitter = new TypedEventEmitter<ClientEvent.ToDeviceEvent, any>();
+        aliceClient.crypto.registerEventHandlers(aliceEventEmitter);
+
        const bobDevice = bobClient.crypto.olmDevice;
-        aliceClient.crypto.downloadKeys = async () => {};
+        aliceClient.crypto.downloadKeys = jest.fn();

        const roomId = "!someroom";

        const now = Date.now();

        // pretend we got an event that we can't decrypt
-        aliceClient.crypto.onToDeviceEvent(new MatrixEvent({
+        aliceEventEmitter.emit(ClientEvent.ToDeviceEvent, new MatrixEvent({
            type: "m.room.encrypted",
            sender: "@bob:example.com",
            content: {
@@ -1,6 +1,6 @@
 /*
 Copyright 2018,2019 New Vector Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -15,17 +15,18 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */

+import { MockedObject } from 'jest-mock';
+
 import '../../../olm-loader';
 import { MemoryCryptoStore } from "../../../../src/crypto/store/memory-crypto-store";
-import { MockStorageApi } from "../../../MockStorageApi";
 import { logger } from "../../../../src/logger";
 import { OlmDevice } from "../../../../src/crypto/OlmDevice";
 import * as olmlib from "../../../../src/crypto/olmlib";
 import { DeviceInfo } from "../../../../src/crypto/deviceinfo";
+import { MatrixClient } from '../../../../src';

 function makeOlmDevice() {
-    const mockStorage = new MockStorageApi();
-    const cryptoStore = new MemoryCryptoStore(mockStorage);
+    const cryptoStore = new MemoryCryptoStore();
    const olmDevice = new OlmDevice(cryptoStore);
    return olmDevice;
 }
@@ -51,8 +52,8 @@ describe("OlmDevice", function() {
        return global.Olm.init();
    });

-    let aliceOlmDevice;
-    let bobOlmDevice;
+    let aliceOlmDevice: OlmDevice;
+    let bobOlmDevice: OlmDevice;

    beforeEach(async function() {
        aliceOlmDevice = makeOlmDevice();
@@ -69,7 +70,7 @@ describe("OlmDevice", function() {
                bobOlmDevice.deviceCurve25519Key,
                sid,
                "The olm or proteus is an aquatic salamander in the family Proteidae",
-            );
+            ) as any; // OlmDevice.encryptMessage has incorrect return type

            const result = await bobOlmDevice.createInboundSession(
                aliceOlmDevice.deviceCurve25519Key,
@@ -96,7 +97,7 @@ describe("OlmDevice", function() {
                bobOlmDevice.deviceCurve25519Key,
                sessionId,
                MESSAGE,
-            );
+            ) as any; // OlmDevice.encryptMessage has incorrect return type

            const bobRecreatedOlmDevice = makeOlmDevice();
            bobRecreatedOlmDevice.init({ fromExportedDevice: exported });
@@ -120,7 +121,7 @@ describe("OlmDevice", function() {
                bobOlmDevice.deviceCurve25519Key,
                sessionId,
                MESSAGE_2,
-            );
+            ) as any; // OlmDevice.encryptMessage has incorrect return type

            const bobRecreatedAgainOlmDevice = makeOlmDevice();
            bobRecreatedAgainOlmDevice.init({ fromExportedDevice: exportedAgain });
@@ -148,7 +149,7 @@ describe("OlmDevice", function() {
                        setTimeout(reject, 500);
                    });
                },
-            };
+            } as unknown as MockedObject<MatrixClient>;
            const devicesByUser = {
                "@bob:example.com": [
                    DeviceInfo.fromStorage({
@@ -205,7 +206,7 @@ describe("OlmDevice", function() {
                        setTimeout(reject, 500);
                    });
                },
-            };
+            } as unknown as MockedObject<MatrixClient>;

            const deviceBobA = DeviceInfo.fromStorage({
                keys: {
@@ -34,7 +34,7 @@ import { IAbortablePromise, MatrixScheduler } from '../../../src';

 const Olm = global.Olm;

-const MegolmDecryption = algorithms.DECRYPTION_CLASSES['m.megolm.v1.aes-sha2'];
+const MegolmDecryption = algorithms.DECRYPTION_CLASSES.get('m.megolm.v1.aes-sha2');

 const ROOM_ID = '!ROOM:ID';

@@ -14,9 +14,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */

-import {
-    IndexedDBCryptoStore,
-} from '../../../src/crypto/store/indexeddb-crypto-store';
+import { CryptoStore } from '../../../src/crypto/store/base';
+import { IndexedDBCryptoStore } from '../../../src/crypto/store/indexeddb-crypto-store';
+import { LocalStorageCryptoStore } from '../../../src/crypto/store/localStorage-crypto-store';
 import { MemoryCryptoStore } from '../../../src/crypto/store/memory-crypto-store';
 import { RoomKeyRequestState } from '../../../src/crypto/OutgoingRoomKeyRequestManager';

@@ -26,36 +26,39 @@ import 'jest-localstorage-mock';
 const requests = [
    {
        requestId: "A",
-        requestBody: { session_id: "A", room_id: "A" },
+        requestBody: { session_id: "A", room_id: "A", sender_key: "A", algorithm: "m.megolm.v1.aes-sha2" },
        state: RoomKeyRequestState.Sent,
+        recipients: [
+            { userId: "@alice:example.com", deviceId: "*" },
+            { userId: "@becca:example.com", deviceId: "foobarbaz" },
+        ],
    },
    {
        requestId: "B",
-        requestBody: { session_id: "B", room_id: "B" },
+        requestBody: { session_id: "B", room_id: "B", sender_key: "B", algorithm: "m.megolm.v1.aes-sha2" },
        state: RoomKeyRequestState.Sent,
+        recipients: [
+            { userId: "@alice:example.com", deviceId: "*" },
+            { userId: "@carrie:example.com", deviceId: "barbazquux" },
+        ],
    },
    {
        requestId: "C",
-        requestBody: { session_id: "C", room_id: "C" },
+        requestBody: { session_id: "C", room_id: "C", sender_key: "B", algorithm: "m.megolm.v1.aes-sha2" },
        state: RoomKeyRequestState.Unsent,
+        recipients: [
+            { userId: "@becca:example.com", deviceId: "foobarbaz" },
+        ],
    },
 ];

 describe.each([
    ["IndexedDBCryptoStore",
        () => new IndexedDBCryptoStore(global.indexedDB, "tests")],
-    ["LocalStorageCryptoStore",
-        () => new IndexedDBCryptoStore(undefined, "tests")],
-    ["MemoryCryptoStore", () => {
-        const store = new IndexedDBCryptoStore(undefined, "tests");
-        // @ts-ignore set private properties
-        store.backend = new MemoryCryptoStore();
-        // @ts-ignore
-        store.backendPromise = Promise.resolve(store.backend);
-        return store;
-    }],
+    ["LocalStorageCryptoStore", () => new LocalStorageCryptoStore(localStorage)],
+    ["MemoryCryptoStore", () => new MemoryCryptoStore()],
 ])("Outgoing room key requests [%s]", function(name, dbFactory) {
-    let store;
+    let store: CryptoStore;

    beforeAll(async () => {
        store = dbFactory();
@@ -75,6 +78,15 @@ describe.each([
            });
        });

+    it("getOutgoingRoomKeyRequestsByTarget retrieves all entries with a given target",
+        async () => {
+            const r = await store.getOutgoingRoomKeyRequestsByTarget(
+                "@becca:example.com", "foobarbaz", [RoomKeyRequestState.Sent],
+            );
+            expect(r).toHaveLength(1);
+            expect(r[0]).toEqual(requests[0]);
+        });
+
    test("getOutgoingRoomKeyRequestByState retrieves any entry in a given state",
        async () => {
            const r =
@@ -218,7 +218,7 @@ describe("SAS verification", function() {
            ]);

            // make sure that it uses the preferred method
-            expect(macMethod).toBe("hkdf-hmac-sha256");
+            expect(macMethod).toBe("org.matrix.msc3783.hkdf-hmac-sha256");
            expect(keyAgreement).toBe("curve25519-hkdf-sha256");

            // make sure Alice and Bob verified each other
@@ -230,6 +230,62 @@ describe("SAS verification", function() {
            expect(aliceDevice.isVerified()).toBeTruthy();
        });

+        it("should be able to verify using the old base64", async () => {
+            // pretend that Alice can only understand the old (incorrect) base64
+            // encoding, and make sure that she can still verify with Bob
+            let macMethod;
+            const aliceOrigSendToDevice = alice.client.sendToDevice.bind(alice.client);
+            alice.client.sendToDevice = (type, map) => {
+                if (type === "m.key.verification.start") {
+                    // Note: this modifies not only the message that Bob
+                    // receives, but also the copy of the message that Alice
+                    // has, since it is the same object.  If this does not
+                    // happen, the verification will fail due to a hash
+                    // commitment mismatch.
+                    map[bob.client.getUserId()][bob.client.deviceId]
+                        .message_authentication_codes = ['hkdf-hmac-sha256'];
+                }
+                return aliceOrigSendToDevice(type, map);
+            };
+            const bobOrigSendToDevice = bob.client.sendToDevice.bind(bob.client);
+            bob.client.sendToDevice = (type, map) => {
+                if (type === "m.key.verification.accept") {
+                    macMethod = map[alice.client.getUserId()][alice.client.deviceId]
+                        .message_authentication_code;
+                }
+                return bobOrigSendToDevice(type, map);
+            };
+
+            alice.httpBackend.when('POST', '/keys/query').respond(200, {
+                failures: {},
+                device_keys: {
+                    "@bob:example.com": BOB_DEVICES,
+                },
+            });
+            bob.httpBackend.when('POST', '/keys/query').respond(200, {
+                failures: {},
+                device_keys: {
+                    "@alice:example.com": ALICE_DEVICES,
+                },
+            });
+
+            await Promise.all([
+                aliceVerifier.verify(),
+                bobPromise.then((verifier) => verifier.verify()),
+                alice.httpBackend.flush(),
+                bob.httpBackend.flush(),
+            ]);
+
+            expect(macMethod).toBe("hkdf-hmac-sha256");
+
+            const bobDevice
+                  = await alice.client.getStoredDevice("@bob:example.com", "Dynabook");
+            expect(bobDevice.isVerified()).toBeTruthy();
+            const aliceDevice
+                  = await bob.client.getStoredDevice("@alice:example.com", "Osborne2");
+            expect(aliceDevice.isVerified()).toBeTruthy();
+        });
+
        it("should be able to verify using the old MAC", async () => {
            // pretend that Alice can only understand the old (incorrect) MAC,
            // and make sure that she can still verify with Bob
@@ -1,26 +1,36 @@
+import { mocked } from 'jest-mock';
+
 import * as utils from "../test-utils/test-utils";
 import { EventTimeline } from "../../src/models/event-timeline";
 import { RoomState } from "../../src/models/room-state";
+import { MatrixClient } from "../../src/matrix";
+import { Room } from "../../src/models/room";
+import { RoomMember } from "../../src/models/room-member";
+import { EventTimelineSet } from "../../src/models/event-timeline-set";

-function mockRoomStates(timeline) {
-    timeline.startState = utils.mock(RoomState, "startState");
-    timeline.endState = utils.mock(RoomState, "endState");
-}
+jest.mock("../../src/models/room-state");

 describe("EventTimeline", function() {
    const roomId = "!foo:bar";
    const userA = "@alice:bar";
    const userB = "@bertha:bar";
-    let timeline;
+    let timeline: EventTimeline;
+
+    const mockClient = {} as unknown as MatrixClient;
+
+    const getTimeline = (): EventTimeline => {
+        const room = new Room(roomId, mockClient, userA);
+        const timelineSet = new EventTimelineSet(room);
+        jest.spyOn(timelineSet.room, 'getUnfilteredTimelineSet').mockReturnValue(timelineSet);
+
+        return new EventTimeline(timelineSet);
+    };

    beforeEach(function() {
-        // XXX: this is a horrid hack; should use sinon or something instead to mock
-        const timelineSet = { room: { roomId: roomId } };
-        timelineSet.room.getUnfilteredTimelineSet = function() {
-            return timelineSet;
-        };
+        // reset any RoomState mocks
+        jest.resetAllMocks();

-        timeline = new EventTimeline(timelineSet);
+        timeline = getTimeline();
    });

    describe("construction", function() {
@@ -31,10 +41,6 @@ describe("EventTimeline", function() {
    });

    describe("initialiseState", function() {
-        beforeEach(function() {
-            mockRoomStates(timeline);
-        });
-
        it("should copy state events to start and end state", function() {
            const events = [
                utils.mkMembership({
@@ -48,11 +54,15 @@ describe("EventTimeline", function() {
                }),
            ];
            timeline.initialiseState(events);
-            expect(timeline.startState.setStateEvents).toHaveBeenCalledWith(
+            // @ts-ignore private prop
+            const timelineStartState = timeline.startState;
+            expect(mocked(timelineStartState).setStateEvents).toHaveBeenCalledWith(
                events,
                { timelineWasEmpty: undefined },
            );
-            expect(timeline.endState.setStateEvents).toHaveBeenCalledWith(
+            // @ts-ignore private prop
+            const timelineEndState = timeline.endState;
+            expect(mocked(timelineEndState).setStateEvents).toHaveBeenCalledWith(
                events,
                { timelineWasEmpty: undefined },
            );
@@ -103,8 +113,8 @@ describe("EventTimeline", function() {
        });

        it("setNeighbouringTimeline should set neighbour", function() {
-            const prev = { a: "a" };
-            const next = { b: "b" };
+            const prev = getTimeline();
+            const next = getTimeline();
            timeline.setNeighbouringTimeline(prev, EventTimeline.BACKWARDS);
            timeline.setNeighbouringTimeline(next, EventTimeline.FORWARDS);
            expect(timeline.getNeighbouringTimeline(EventTimeline.BACKWARDS)).toBe(prev);
@@ -112,8 +122,8 @@ describe("EventTimeline", function() {
        });

        it("setNeighbouringTimeline should throw if called twice", function() {
-            const prev = { a: "a" };
-            const next = { b: "b" };
+            const prev = getTimeline();
+            const next = getTimeline();
            expect(function() {
                timeline.setNeighbouringTimeline(prev, EventTimeline.BACKWARDS);
            }).not.toThrow();
@@ -135,10 +145,6 @@ describe("EventTimeline", function() {
    });

    describe("addEvent", function() {
-        beforeEach(function() {
-            mockRoomStates(timeline);
-        });
-
        const events = [
            utils.mkMessage({
                room: roomId, user: userA, msg: "hungry hungry hungry",
@@ -171,24 +177,22 @@ describe("EventTimeline", function() {
        });

        it("should set event.sender for new and old events", function() {
-            const sentinel = {
-                userId: userA,
-                membership: "join",
-                name: "Alice",
-            };
-            const oldSentinel = {
-                userId: userA,
-                membership: "join",
-                name: "Old Alice",
-            };
-            timeline.getState(EventTimeline.FORWARDS).getSentinelMember
+            const sentinel = new RoomMember(roomId, userA);
+            sentinel.name = "Alice";
+            sentinel.membership = "join";
+
+            const oldSentinel = new RoomMember(roomId, userA);
+            sentinel.name = "Old Alice";
+            sentinel.membership = "join";
+
+            mocked(timeline.getState(EventTimeline.FORWARDS)).getSentinelMember
                .mockImplementation(function(uid) {
                    if (uid === userA) {
                        return sentinel;
                    }
                    return null;
                });
-            timeline.getState(EventTimeline.BACKWARDS).getSentinelMember
+            mocked(timeline.getState(EventTimeline.BACKWARDS)).getSentinelMember
                .mockImplementation(function(uid) {
                    if (uid === userA) {
                        return oldSentinel;
@@ -212,43 +216,41 @@ describe("EventTimeline", function() {
        });

        it("should set event.target for new and old m.room.member events",
-        function() {
-            const sentinel = {
-                userId: userA,
-                membership: "join",
-                name: "Alice",
-            };
-            const oldSentinel = {
-                userId: userA,
-                membership: "join",
-                name: "Old Alice",
-            };
-            timeline.getState(EventTimeline.FORWARDS).getSentinelMember
-                .mockImplementation(function(uid) {
-                    if (uid === userA) {
-                        return sentinel;
-                    }
-                    return null;
-                });
-            timeline.getState(EventTimeline.BACKWARDS).getSentinelMember
-                .mockImplementation(function(uid) {
-                    if (uid === userA) {
-                        return oldSentinel;
-                    }
-                    return null;
-                });
+            function() {
+                const sentinel = new RoomMember(roomId, userA);
+                sentinel.name = "Alice";
+                sentinel.membership = "join";

-            const newEv = utils.mkMembership({
-                room: roomId, mship: "invite", user: userB, skey: userA, event: true,
+                const oldSentinel = new RoomMember(roomId, userA);
+                sentinel.name = "Old Alice";
+                sentinel.membership = "join";
+
+                mocked(timeline.getState(EventTimeline.FORWARDS)).getSentinelMember
+                    .mockImplementation(function(uid) {
+                        if (uid === userA) {
+                            return sentinel;
+                        }
+                        return null;
+                    });
+                mocked(timeline.getState(EventTimeline.BACKWARDS)).getSentinelMember
+                    .mockImplementation(function(uid) {
+                        if (uid === userA) {
+                            return oldSentinel;
+                        }
+                        return null;
+                    });
+
+                const newEv = utils.mkMembership({
+                    room: roomId, mship: "invite", user: userB, skey: userA, event: true,
+                });
+                const oldEv = utils.mkMembership({
+                    room: roomId, mship: "ban", user: userB, skey: userA, event: true,
+                });
+                timeline.addEvent(newEv, { toStartOfTimeline: false });
+                expect(newEv.target).toEqual(sentinel);
+                timeline.addEvent(oldEv, { toStartOfTimeline: true });
+                expect(oldEv.target).toEqual(oldSentinel);
            });
-            const oldEv = utils.mkMembership({
-                room: roomId, mship: "ban", user: userB, skey: userA, event: true,
-            });
-            timeline.addEvent(newEv, { toStartOfTimeline: false });
-            expect(newEv.target).toEqual(sentinel);
-            timeline.addEvent(oldEv, { toStartOfTimeline: true });
-            expect(oldEv.target).toEqual(oldSentinel);
-        });

        it("should call setStateEvents on the right RoomState with the right " +
           "forwardLooking value for new events", function() {
@@ -310,7 +312,11 @@ describe("EventTimeline", function() {

        it("Make sure legacy overload passing options directly as parameters still works", () => {
            expect(() => timeline.addEvent(events[0], { toStartOfTimeline: true })).not.toThrow();
-            expect(() => timeline.addEvent(events[0], { stateContext: new RoomState() })).not.toThrow();
+            // @ts-ignore stateContext is not a valid param
+            expect(() => timeline.addEvent(events[0], { stateContext: new RoomState(roomId) })).not.toThrow();
+            expect(() => timeline.addEvent(events[0],
+                { toStartOfTimeline: false, roomState: new RoomState(roomId) },
+            )).not.toThrow();
        });
    });

@@ -364,14 +370,14 @@ describe("EventTimeline", function() {
        // - removing the last event got baseIndex into such a state that
        // further addEvent(ev, false) calls made the index increase.
        it("should not make baseIndex assplode when removing the last event",
-           function() {
-               timeline.addEvent(events[0], { toStartOfTimeline: true });
-               timeline.removeEvent(events[0].getId());
-               const initialIndex = timeline.getBaseIndex();
-               timeline.addEvent(events[1], { toStartOfTimeline: false });
-               timeline.addEvent(events[2], { toStartOfTimeline: false });
-               expect(timeline.getBaseIndex()).toEqual(initialIndex);
-               expect(timeline.getEvents().length).toEqual(2);
-           });
+            function() {
+                timeline.addEvent(events[0], { toStartOfTimeline: true });
+                timeline.removeEvent(events[0].getId());
+                const initialIndex = timeline.getBaseIndex();
+                timeline.addEvent(events[1], { toStartOfTimeline: false });
+                timeline.addEvent(events[2], { toStartOfTimeline: false });
+                expect(timeline.getBaseIndex()).toEqual(initialIndex);
+                expect(timeline.getEvents().length).toEqual(2);
+            });
    });
 });
@@ -1,6 +1,6 @@
 /*
 Copyright 2017 New Vector Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -15,16 +15,16 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */

-import { logger } from "../../src/logger";
 import { MatrixEvent } from "../../src/models/event";

 describe("MatrixEvent", () => {
    describe(".attemptDecryption", () => {
        let encryptedEvent;
+        const eventId = 'test_encrypted_event';

        beforeEach(() => {
            encryptedEvent = new MatrixEvent({
-                id: 'test_encrypted_event',
+                event_id: eventId,
                type: 'm.room.encrypted',
                content: {
                    ciphertext: 'secrets',
@@ -32,45 +32,34 @@ describe("MatrixEvent", () => {
            });
        });

-        it('should retry decryption if a retry is queued', () => {
-            let callCount = 0;
-
-            let prom2;
-            let prom2Fulfilled = false;
+        it('should retry decryption if a retry is queued', async () => {
+            const eventAttemptDecryptionSpy = jest.spyOn(encryptedEvent, 'attemptDecryption');

            const crypto = {
-                decryptEvent: function() {
-                    ++callCount;
-                    logger.log(`decrypt: ${callCount}`);
-                    if (callCount == 1) {
+                decryptEvent: jest.fn()
+                    .mockImplementationOnce(() => {
                        // schedule a second decryption attempt while
                        // the first one is still running.
-                        prom2 = encryptedEvent.attemptDecryption(crypto);
-                        prom2.then(() => prom2Fulfilled = true);
+                        encryptedEvent.attemptDecryption(crypto);

                        const error = new Error("nope");
                        error.name = 'DecryptionError';
                        return Promise.reject(error);
-                    } else {
-                        expect(prom2Fulfilled).toBe(
-                            false, 'second attemptDecryption resolved too soon');
-
+                    })
+                    .mockImplementationOnce(() => {
                        return Promise.resolve({
                            clearEvent: {
                                type: 'm.room.message',
                            },
                        });
-                    }
-                },
+                    }),
            };

-            return encryptedEvent.attemptDecryption(crypto).then(() => {
-                expect(callCount).toEqual(2);
-                expect(encryptedEvent.getType()).toEqual('m.room.message');
+            await encryptedEvent.attemptDecryption(crypto);

-                // make sure the second attemptDecryption resolves
-                return prom2;
-            });
+            expect(eventAttemptDecryptionSpy).toHaveBeenCalledTimes(2);
+            expect(crypto.decryptEvent).toHaveBeenCalledTimes(2);
+            expect(encryptedEvent.getType()).toEqual('m.room.message');
        });
    });
 });
@@ -1,9 +1,9 @@
-import { Filter } from "../../src/filter";
+import { Filter, IFilterDefinition } from "../../src/filter";

 describe("Filter", function() {
    const filterId = "f1lt3ring15g00d4ursoul";
    const userId = "@sir_arthur_david:humming.tiger";
-    let filter;
+    let filter: Filter;

    beforeEach(function() {
        filter = new Filter(userId);
@@ -37,7 +37,7 @@ describe("Filter", function() {
    describe("setDefinition/getDefinition", function() {
        it("should set and get the filter body", function() {
            const definition = {
-                event_format: "client",
+                event_format: "client" as IFilterDefinition['event_format'],
            };
            filter.setDefinition(definition);
            expect(filter.getDefinition()).toEqual(definition);
@@ -1,280 +0,0 @@
-/*
-Copyright 2016 OpenMarket Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-import { logger } from "../../src/logger";
-import { InteractiveAuth } from "../../src/interactive-auth";
-import { MatrixError } from "../../src/http-api";
-import { sleep } from "../../src/utils";
-import { randomString } from "../../src/randomstring";
-
-// Trivial client object to test interactive auth
-// (we do not need TestClient here)
-class FakeClient {
-    generateClientSecret() {
-        return "testcl1Ent5EcreT";
-    }
-}
-
-describe("InteractiveAuth", function() {
-    it("should start an auth stage and complete it", function() {
-        const doRequest = jest.fn();
-        const stateUpdated = jest.fn();
-
-        const ia = new InteractiveAuth({
-            matrixClient: new FakeClient(),
-            doRequest: doRequest,
-            stateUpdated: stateUpdated,
-            authData: {
-                session: "sessionId",
-                flows: [
-                    { stages: ["logintype"] },
-                ],
-                params: {
-                    "logintype": { param: "aa" },
-                },
-            },
-        });
-
-        expect(ia.getSessionId()).toEqual("sessionId");
-        expect(ia.getStageParams("logintype")).toEqual({
-            param: "aa",
-        });
-
-        // first we expect a call here
-        stateUpdated.mockImplementation(function(stage) {
-            logger.log('aaaa');
-            expect(stage).toEqual("logintype");
-            ia.submitAuthDict({
-                type: "logintype",
-                foo: "bar",
-            });
-        });
-
-        // .. which should trigger a call here
-        const requestRes = { "a": "b" };
-        doRequest.mockImplementation(function(authData) {
-            logger.log('cccc');
-            expect(authData).toEqual({
-                session: "sessionId",
-                type: "logintype",
-                foo: "bar",
-            });
-            return Promise.resolve(requestRes);
-        });
-
-        return ia.attemptAuth().then(function(res) {
-            expect(res).toBe(requestRes);
-            expect(doRequest).toBeCalledTimes(1);
-            expect(stateUpdated).toBeCalledTimes(1);
-        });
-    });
-
-    it("should make a request if no authdata is provided", function() {
-        const doRequest = jest.fn();
-        const stateUpdated = jest.fn();
-
-        const ia = new InteractiveAuth({
-            matrixClient: new FakeClient(),
-            stateUpdated: stateUpdated,
-            doRequest: doRequest,
-        });
-
-        expect(ia.getSessionId()).toBe(undefined);
-        expect(ia.getStageParams("logintype")).toBe(undefined);
-
-        // first we expect a call to doRequest
-        doRequest.mockImplementation(function(authData) {
-            logger.log("request1", authData);
-            expect(authData).toEqual(null); // first request should be null
-            const err = new MatrixError({
-                session: "sessionId",
-                flows: [
-                    { stages: ["logintype"] },
-                ],
-                params: {
-                    "logintype": { param: "aa" },
-                },
-            });
-            err.httpStatus = 401;
-            throw err;
-        });
-
-        // .. which should be followed by a call to stateUpdated
-        const requestRes = { "a": "b" };
-        stateUpdated.mockImplementation(function(stage) {
-            expect(stage).toEqual("logintype");
-            expect(ia.getSessionId()).toEqual("sessionId");
-            expect(ia.getStageParams("logintype")).toEqual({
-                param: "aa",
-            });
-
-            // submitAuthDict should trigger another call to doRequest
-            doRequest.mockImplementation(function(authData) {
-                logger.log("request2", authData);
-                expect(authData).toEqual({
-                    session: "sessionId",
-                    type: "logintype",
-                    foo: "bar",
-                });
-                return Promise.resolve(requestRes);
-            });
-
-            ia.submitAuthDict({
-                type: "logintype",
-                foo: "bar",
-            });
-        });
-
-        return ia.attemptAuth().then(function(res) {
-            expect(res).toBe(requestRes);
-            expect(doRequest).toBeCalledTimes(2);
-            expect(stateUpdated).toBeCalledTimes(1);
-        });
-    });
-
-    it("should start an auth stage and reject if no auth flow", function() {
-        const doRequest = jest.fn();
-        const stateUpdated = jest.fn();
-
-        const ia = new InteractiveAuth({
-            matrixClient: new FakeClient(),
-            doRequest: doRequest,
-            stateUpdated: stateUpdated,
-        });
-
-        doRequest.mockImplementation(function(authData) {
-            logger.log("request1", authData);
-            expect(authData).toEqual(null); // first request should be null
-            const err = new MatrixError({
-                session: "sessionId",
-                flows: [],
-                params: {
-                    "logintype": { param: "aa" },
-                },
-            });
-            err.httpStatus = 401;
-            throw err;
-        });
-
-        return ia.attemptAuth().catch(function(error) {
-            expect(error.message).toBe('No appropriate authentication flow found');
-        });
-    });
-
-    describe("requestEmailToken", () => {
-        it("increases auth attempts", async () => {
-            const doRequest = jest.fn();
-            const stateUpdated = jest.fn();
-            const requestEmailToken = jest.fn();
-            requestEmailToken.mockImplementation(async () => ({ sid: "" }));
-
-            const ia = new InteractiveAuth({
-                matrixClient: new FakeClient(),
-                doRequest, stateUpdated, requestEmailToken,
-            });
-
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 1, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 2, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 3, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 4, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 5, undefined);
-        });
-
-        it("increases auth attempts", async () => {
-            const doRequest = jest.fn();
-            const stateUpdated = jest.fn();
-            const requestEmailToken = jest.fn();
-            requestEmailToken.mockImplementation(async () => ({ sid: "" }));
-
-            const ia = new InteractiveAuth({
-                matrixClient: new FakeClient(),
-                doRequest, stateUpdated, requestEmailToken,
-            });
-
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 1, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 2, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 3, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 4, undefined);
-            requestEmailToken.mockClear();
-            await ia.requestEmailToken();
-            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 5, undefined);
-        });
-
-        it("passes errors through", async () => {
-            const doRequest = jest.fn();
-            const stateUpdated = jest.fn();
-            const requestEmailToken = jest.fn();
-            requestEmailToken.mockImplementation(async () => {
-                throw new Error("unspecific network error");
-            });
-
-            const ia = new InteractiveAuth({
-                matrixClient: new FakeClient(),
-                doRequest, stateUpdated, requestEmailToken,
-            });
-
-            expect(async () => await ia.requestEmailToken()).rejects.toThrowError("unspecific network error");
-        });
-
-        it("only starts one request at a time", async () => {
-            const doRequest = jest.fn();
-            const stateUpdated = jest.fn();
-            const requestEmailToken = jest.fn();
-            requestEmailToken.mockImplementation(() => sleep(500, { sid: "" }));
-
-            const ia = new InteractiveAuth({
-                matrixClient: new FakeClient(),
-                doRequest, stateUpdated, requestEmailToken,
-            });
-
-            await Promise.all([ia.requestEmailToken(), ia.requestEmailToken(), ia.requestEmailToken()]);
-            expect(requestEmailToken).toHaveBeenCalledTimes(1);
-        });
-
-        it("stores result in email sid", async () => {
-            const doRequest = jest.fn();
-            const stateUpdated = jest.fn();
-            const requestEmailToken = jest.fn();
-            const sid = randomString(24);
-            requestEmailToken.mockImplementation(() => sleep(500, { sid }));
-
-            const ia = new InteractiveAuth({
-                matrixClient: new FakeClient(),
-                doRequest, stateUpdated, requestEmailToken,
-            });
-
-            await ia.requestEmailToken();
-            expect(ia.getEmailSid()).toEqual(sid);
-        });
-    });
-});
@@ -0,0 +1,552 @@
+/*
+Copyright 2016 OpenMarket Ltd
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { MatrixClient } from "../../src/client";
+import { logger } from "../../src/logger";
+import { InteractiveAuth, AuthType } from "../../src/interactive-auth";
+import { MatrixError } from "../../src/http-api";
+import { sleep } from "../../src/utils";
+import { randomString } from "../../src/randomstring";
+
+// Trivial client object to test interactive auth
+// (we do not need TestClient here)
+class FakeClient {
+    generateClientSecret() {
+        return "testcl1Ent5EcreT";
+    }
+}
+
+const getFakeClient = (): MatrixClient => new FakeClient() as unknown as MatrixClient;
+
+describe("InteractiveAuth", () => {
+    it("should start an auth stage and complete it", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest: doRequest,
+            stateUpdated: stateUpdated,
+            requestEmailToken: jest.fn(),
+            authData: {
+                session: "sessionId",
+                flows: [
+                    { stages: [AuthType.Password] },
+                ],
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+            },
+        });
+
+        expect(ia.getSessionId()).toEqual("sessionId");
+        expect(ia.getStageParams(AuthType.Password)).toEqual({
+            param: "aa",
+        });
+
+        // first we expect a call here
+        stateUpdated.mockImplementation((stage) => {
+            logger.log('aaaa');
+            expect(stage).toEqual(AuthType.Password);
+            ia.submitAuthDict({
+                type: AuthType.Password,
+            });
+        });
+
+        // .. which should trigger a call here
+        const requestRes = { "a": "b" };
+        doRequest.mockImplementation(async (authData) => {
+            logger.log('cccc');
+            expect(authData).toEqual({
+                session: "sessionId",
+                type: AuthType.Password,
+            });
+            return requestRes;
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(1);
+        expect(stateUpdated).toBeCalledTimes(1);
+    });
+
+    it("should handle auth errcode presence ", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest: doRequest,
+            stateUpdated: stateUpdated,
+            requestEmailToken: jest.fn(),
+            authData: {
+                session: "sessionId",
+                flows: [
+                    { stages: [AuthType.Password] },
+                ],
+                errcode: "MockError0",
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+            },
+        });
+
+        expect(ia.getSessionId()).toEqual("sessionId");
+        expect(ia.getStageParams(AuthType.Password)).toEqual({
+            param: "aa",
+        });
+
+        // first we expect a call here
+        stateUpdated.mockImplementation((stage) => {
+            logger.log('aaaa');
+            expect(stage).toEqual(AuthType.Password);
+            ia.submitAuthDict({
+                type: AuthType.Password,
+            });
+        });
+
+        // .. which should trigger a call here
+        const requestRes = { "a": "b" };
+        doRequest.mockImplementation(async (authData) => {
+            logger.log('cccc');
+            expect(authData).toEqual({
+                session: "sessionId",
+                type: AuthType.Password,
+            });
+            return requestRes;
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(1);
+        expect(stateUpdated).toBeCalledTimes(1);
+    });
+
+    it("should handle set emailSid for email flow", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            doRequest,
+            stateUpdated,
+            requestEmailToken,
+            matrixClient: getFakeClient(),
+            emailSid: 'myEmailSid',
+            authData: {
+                session: "sessionId",
+                flows: [
+                    { stages: [AuthType.Email, AuthType.Password] },
+                ],
+                params: {
+                    [AuthType.Email]: { param: "aa" },
+                    [AuthType.Password]: { param: "bb" },
+                },
+            },
+        });
+
+        expect(ia.getSessionId()).toEqual("sessionId");
+        expect(ia.getStageParams(AuthType.Email)).toEqual({
+            param: "aa",
+        });
+
+        // first we expect a call here
+        stateUpdated.mockImplementation((stage) => {
+            logger.log('husky');
+            expect(stage).toEqual(AuthType.Email);
+            ia.submitAuthDict({
+                type: AuthType.Email,
+            });
+        });
+
+        // .. which should trigger a call here
+        const requestRes = { "a": "b" };
+        doRequest.mockImplementation(async (authData) => {
+            logger.log('barfoo');
+            expect(authData).toEqual({
+                session: "sessionId",
+                type: AuthType.Email,
+            });
+            return requestRes;
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(1);
+        expect(stateUpdated).toBeCalledTimes(1);
+        expect(requestEmailToken).toBeCalledTimes(0);
+        expect(ia.getEmailSid()).toBe("myEmailSid");
+    });
+
+    it("should make a request if no authdata is provided", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            stateUpdated,
+            doRequest,
+            requestEmailToken,
+        });
+
+        expect(ia.getSessionId()).toBe(undefined);
+        expect(ia.getStageParams(AuthType.Password)).toBe(undefined);
+
+        // first we expect a call to doRequest
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual(null); // first request should be null
+            const err = new MatrixError({
+                session: "sessionId",
+                flows: [
+                    { stages: [AuthType.Password] },
+                ],
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+            });
+            err.httpStatus = 401;
+            throw err;
+        });
+
+        // .. which should be followed by a call to stateUpdated
+        const requestRes = { "a": "b" };
+        stateUpdated.mockImplementation((stage) => {
+            expect(stage).toEqual(AuthType.Password);
+            expect(ia.getSessionId()).toEqual("sessionId");
+            expect(ia.getStageParams(AuthType.Password)).toEqual({
+                param: "aa",
+            });
+
+            // submitAuthDict should trigger another call to doRequest
+            doRequest.mockImplementation(async (authData) => {
+                logger.log("request2", authData);
+                expect(authData).toEqual({
+                    session: "sessionId",
+                    type: AuthType.Password,
+                });
+                return requestRes;
+            });
+
+            ia.submitAuthDict({
+                type: AuthType.Password,
+            });
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(2);
+        expect(stateUpdated).toBeCalledTimes(1);
+    });
+
+    it("should make a request if authdata is null", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            authData: null,
+            matrixClient: getFakeClient(),
+            stateUpdated,
+            doRequest,
+            requestEmailToken,
+        });
+
+        expect(ia.getSessionId()).toBe(undefined);
+        expect(ia.getStageParams(AuthType.Password)).toBe(undefined);
+
+        // first we expect a call to doRequest
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual(null); // first request should be null
+            const err = new MatrixError({
+                session: "sessionId",
+                flows: [
+                    { stages: [AuthType.Password] },
+                ],
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+            });
+            err.httpStatus = 401;
+            throw err;
+        });
+
+        // .. which should be followed by a call to stateUpdated
+        const requestRes = { "a": "b" };
+        stateUpdated.mockImplementation((stage) => {
+            expect(stage).toEqual(AuthType.Password);
+            expect(ia.getSessionId()).toEqual("sessionId");
+            expect(ia.getStageParams(AuthType.Password)).toEqual({
+                param: "aa",
+            });
+
+            // submitAuthDict should trigger another call to doRequest
+            doRequest.mockImplementation(async (authData) => {
+                logger.log("request2", authData);
+                expect(authData).toEqual({
+                    session: "sessionId",
+                    type: AuthType.Password,
+                });
+                return requestRes;
+            });
+
+            ia.submitAuthDict({
+                type: AuthType.Password,
+            });
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(2);
+        expect(stateUpdated).toBeCalledTimes(1);
+    });
+
+    it("should start an auth stage and reject if no auth flow", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest,
+            stateUpdated,
+            requestEmailToken,
+        });
+
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual(null); // first request should be null
+            const err = new MatrixError({
+                session: "sessionId",
+                flows: [],
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+            });
+            err.httpStatus = 401;
+            throw err;
+        });
+
+        await expect(ia.attemptAuth.bind(ia)).rejects.toThrow(
+            new Error('No appropriate authentication flow found'),
+        );
+    });
+
+    it("should start an auth stage and reject if no auth flow but has session", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest,
+            stateUpdated,
+            requestEmailToken,
+            authData: {
+            },
+            sessionId: "sessionId",
+        });
+
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual({ "session": "sessionId" }); // has existing sessionId
+            const err = new MatrixError({
+                session: "sessionId",
+                flows: [],
+                params: {
+                    [AuthType.Password]: { param: "aa" },
+                },
+                error: "Mock Error 1",
+                errcode: "MOCKERR1",
+            });
+            err.httpStatus = 401;
+            throw err;
+        });
+
+        await expect(ia.attemptAuth.bind(ia)).rejects.toThrow(
+            new Error('No appropriate authentication flow found'),
+        );
+    });
+
+    it("should handle unexpected error types without data propery set", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest,
+            stateUpdated,
+            requestEmailToken,
+            authData: {
+                session: "sessionId",
+            },
+        });
+
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual({ "session": "sessionId" }); // has existing sessionId
+            const err = new Error('myerror');
+            (err as any).httpStatus = 401;
+            throw err;
+        });
+
+        await expect(ia.attemptAuth.bind(ia)).rejects.toThrow(
+            new Error("myerror"),
+        );
+    });
+
+    it("should allow dummy auth", async () => {
+        const doRequest = jest.fn();
+        const stateUpdated = jest.fn();
+        const requestEmailToken = jest.fn();
+
+        const ia = new InteractiveAuth({
+            matrixClient: getFakeClient(),
+            doRequest,
+            stateUpdated,
+            requestEmailToken,
+            authData: {
+                session: 'sessionId',
+                flows: [
+                    { stages: [AuthType.Dummy] },
+                ],
+                params: {},
+            },
+        });
+
+        const requestRes = { "a": "b" };
+        doRequest.mockImplementation((authData) => {
+            logger.log("request1", authData);
+            expect(authData).toEqual({
+                session: "sessionId",
+                type: AuthType.Dummy,
+            });
+            return requestRes;
+        });
+
+        const res = await ia.attemptAuth();
+        expect(res).toBe(requestRes);
+        expect(doRequest).toBeCalledTimes(1);
+        expect(stateUpdated).toBeCalledTimes(0);
+    });
+
+    describe("requestEmailToken", () => {
+        it("increases auth attempts", async () => {
+            const doRequest = jest.fn();
+            const stateUpdated = jest.fn();
+            const requestEmailToken = jest.fn();
+            requestEmailToken.mockImplementation(async () => ({ sid: "" }));
+
+            const ia = new InteractiveAuth({
+                matrixClient: getFakeClient(),
+                doRequest, stateUpdated, requestEmailToken,
+            });
+
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 1, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 2, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 3, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 4, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 5, undefined);
+        });
+
+        it("increases auth attempts", async () => {
+            const doRequest = jest.fn();
+            const stateUpdated = jest.fn();
+            const requestEmailToken = jest.fn();
+            requestEmailToken.mockImplementation(async () => ({ sid: "" }));
+
+            const ia = new InteractiveAuth({
+                matrixClient: getFakeClient(),
+                doRequest, stateUpdated, requestEmailToken,
+            });
+
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 1, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 2, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 3, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 4, undefined);
+            requestEmailToken.mockClear();
+            await ia.requestEmailToken();
+            expect(requestEmailToken).toHaveBeenLastCalledWith(undefined, ia.getClientSecret(), 5, undefined);
+        });
+
+        it("passes errors through", async () => {
+            const doRequest = jest.fn();
+            const stateUpdated = jest.fn();
+            const requestEmailToken = jest.fn();
+            requestEmailToken.mockImplementation(async () => {
+                throw new Error("unspecific network error");
+            });
+
+            const ia = new InteractiveAuth({
+                matrixClient: getFakeClient(),
+                doRequest, stateUpdated, requestEmailToken,
+            });
+
+            await expect(ia.requestEmailToken.bind(ia)).rejects.toThrowError("unspecific network error");
+        });
+
+        it("only starts one request at a time", async () => {
+            const doRequest = jest.fn();
+            const stateUpdated = jest.fn();
+            const requestEmailToken = jest.fn();
+            requestEmailToken.mockImplementation(() => sleep(500, { sid: "" }));
+
+            const ia = new InteractiveAuth({
+                matrixClient: getFakeClient(),
+                doRequest, stateUpdated, requestEmailToken,
+            });
+
+            await Promise.all([ia.requestEmailToken(), ia.requestEmailToken(), ia.requestEmailToken()]);
+            expect(requestEmailToken).toHaveBeenCalledTimes(1);
+        });
+
+        it("stores result in email sid", async () => {
+            const doRequest = jest.fn();
+            const stateUpdated = jest.fn();
+            const requestEmailToken = jest.fn();
+            const sid = randomString(24);
+            requestEmailToken.mockImplementation(() => sleep(500, { sid }));
+
+            const ia = new InteractiveAuth({
+                matrixClient: getFakeClient(),
+                doRequest, stateUpdated, requestEmailToken,
+            });
+
+            await ia.requestEmailToken();
+            expect(ia.getEmailSid()).toEqual(sid);
+        });
+    });
+});
@@ -1,7 +1,7 @@
 import { TestClient } from '../TestClient';

 describe('Login request', function() {
-    let client;
+    let client: TestClient;

    beforeEach(function() {
        client = new TestClient();
@@ -14,8 +14,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */

+import { mocked } from "jest-mock";
+
 import { logger } from "../../src/logger";
-import { MatrixClient } from "../../src/client";
+import { MatrixClient, ClientEvent } from "../../src/client";
 import { Filter } from "../../src/filter";
 import { DEFAULT_TREE_POWER_LEVELS_TEMPLATE } from "../../src/models/MSC3089TreeSpace";
 import {
@@ -27,6 +29,7 @@ import {
    UNSTABLE_MSC3089_TREE_SUBTYPE,
 } from "../../src/@types/event";
 import { MEGOLM_ALGORITHM } from "../../src/crypto/olmlib";
+import { Crypto } from "../../src/crypto";
 import { EventStatus, MatrixEvent } from "../../src/models/event";
 import { Preset } from "../../src/@types/partials";
 import { ReceiptType } from "../../src/@types/read_receipts";
@@ -34,10 +37,16 @@ import * as testUtils from "../test-utils/test-utils";
 import { makeBeaconInfoContent } from "../../src/content-helpers";
 import { M_BEACON_INFO } from "../../src/@types/beacon";
 import { ContentHelpers, Room } from "../../src";
+import { supportsMatrixCall } from "../../src/webrtc/call";
 import { makeBeaconEvent } from "../test-utils/beacon";

 jest.useFakeTimers();

+jest.mock("../../src/webrtc/call", () => ({
+    ...jest.requireActual("../../src/webrtc/call"),
+    supportsMatrixCall: jest.fn(() => false),
+}));
+
 describe("MatrixClient", function() {
    const userId = "@alice:bar";
    const identityServerUrl = "https://identity.server";
@@ -159,6 +168,24 @@ describe("MatrixClient", function() {
        return new Promise(() => {});
    }

+    function makeClient() {
+        client = new MatrixClient({
+            baseUrl: "https://my.home.server",
+            idBaseUrl: identityServerUrl,
+            accessToken: "my.access.token",
+            request: function() {} as any, // NOP
+            store: store,
+            scheduler: scheduler,
+            userId: userId,
+        });
+        // FIXME: We shouldn't be yanking http like this.
+        client.http = [
+            "authedRequest", "getContentUri", "request", "uploadContent",
+        ].reduce((r, k) => { r[k] = jest.fn(); return r; }, {});
+        client.http.authedRequest.mockImplementation(httpReq);
+        client.http.request.mockImplementation(httpReq);
+    }
+
    beforeEach(function() {
        scheduler = [
            "getQueueForEvent", "queueEvent", "removeEventFromQueue",
@@ -176,21 +203,7 @@ describe("MatrixClient", function() {
        store.getClientOptions = jest.fn().mockReturnValue(Promise.resolve(null));
        store.storeClientOptions = jest.fn().mockReturnValue(Promise.resolve(null));
        store.isNewlyCreated = jest.fn().mockReturnValue(Promise.resolve(true));
-        client = new MatrixClient({
-            baseUrl: "https://my.home.server",
-            idBaseUrl: identityServerUrl,
-            accessToken: "my.access.token",
-            request: function() {} as any, // NOP
-            store: store,
-            scheduler: scheduler,
-            userId: userId,
-        });
-        // FIXME: We shouldn't be yanking http like this.
-        client.http = [
-            "authedRequest", "getContentUri", "request", "uploadContent",
-        ].reduce((r, k) => { r[k] = jest.fn(); return r; }, {});
-        client.http.authedRequest.mockImplementation(httpReq);
-        client.http.request.mockImplementation(httpReq);
+        makeClient();

        // set reasonable working defaults
        acceptKeepalives = true;
@@ -414,7 +427,7 @@ describe("MatrixClient", function() {
                }
            });
        });
-        await client.startClient();
+        await client.startClient({ filter });
        await syncPromise;
    });

@@ -1297,4 +1310,106 @@ describe("MatrixClient", function() {
            expect(result!.aliases).toEqual(response.aliases);
        });
    });
+
+    describe("pollingTurnServers", () => {
+        afterEach(() => {
+            mocked(supportsMatrixCall).mockReset();
+        });
+
+        it("is false if the client isn't started", () => {
+            expect(client.clientRunning).toBe(false);
+            expect(client.pollingTurnServers).toBe(false);
+        });
+
+        it("is false if VoIP is not supported", async () => {
+            mocked(supportsMatrixCall).mockReturnValue(false);
+            makeClient(); // create the client a second time so it picks up the supportsMatrixCall mock
+            await client.startClient();
+            expect(client.pollingTurnServers).toBe(false);
+        });
+
+        it("is true if VoIP is supported", async () => {
+            mocked(supportsMatrixCall).mockReturnValue(true);
+            makeClient(); // create the client a second time so it picks up the supportsMatrixCall mock
+            await client.startClient();
+            expect(client.pollingTurnServers).toBe(true);
+        });
+    });
+
+    describe("checkTurnServers", () => {
+        beforeAll(() => {
+            mocked(supportsMatrixCall).mockReturnValue(true);
+        });
+
+        beforeEach(() => {
+            makeClient(); // create the client a second time so it picks up the supportsMatrixCall mock
+        });
+
+        afterAll(() => {
+            mocked(supportsMatrixCall).mockReset();
+        });
+
+        it("emits an event when new TURN creds are found", async () => {
+            const turnServer = {
+                uris: [
+                    "turn:turn.example.com:3478?transport=udp",
+                    "turn:10.20.30.40:3478?transport=tcp",
+                    "turns:10.20.30.40:443?transport=tcp",
+                ],
+                username: "1443779631:@user:example.com",
+                password: "JlKfBy1QwLrO20385QyAtEyIv0=",
+            };
+            jest.spyOn(client, "turnServer").mockResolvedValue(turnServer);
+
+            const events: any[][] = [];
+            const onTurnServers = (...args) => events.push(args);
+            client.on(ClientEvent.TurnServers, onTurnServers);
+            expect(await client.checkTurnServers()).toBe(true);
+            client.off(ClientEvent.TurnServers, onTurnServers);
+            expect(events).toEqual([[[{
+                urls: turnServer.uris,
+                username: turnServer.username,
+                credential: turnServer.password,
+            }]]]);
+        });
+
+        it("emits an event when an error occurs", async () => {
+            const error = new Error(":(");
+            jest.spyOn(client, "turnServer").mockRejectedValue(error);
+
+            const events: any[][] = [];
+            const onTurnServersError = (...args) => events.push(args);
+            client.on(ClientEvent.TurnServersError, onTurnServersError);
+            expect(await client.checkTurnServers()).toBe(false);
+            client.off(ClientEvent.TurnServersError, onTurnServersError);
+            expect(events).toEqual([[error, false]]); // non-fatal
+        });
+
+        it("considers 403 errors fatal", async () => {
+            const error = { httpStatus: 403 };
+            jest.spyOn(client, "turnServer").mockRejectedValue(error);
+
+            const events: any[][] = [];
+            const onTurnServersError = (...args) => events.push(args);
+            client.on(ClientEvent.TurnServersError, onTurnServersError);
+            expect(await client.checkTurnServers()).toBe(false);
+            client.off(ClientEvent.TurnServersError, onTurnServersError);
+            expect(events).toEqual([[error, true]]); // fatal
+        });
+    });
+
+    describe("encryptAndSendToDevices", () => {
+        it("throws an error if crypto is unavailable", () => {
+            client.crypto = undefined;
+            expect(() => client.encryptAndSendToDevices([], {})).toThrow();
+        });
+
+        it("is an alias for the crypto method", async () => {
+            client.crypto = testUtils.mock(Crypto, "Crypto");
+            const deviceInfos = [];
+            const payload = {};
+            await client.encryptAndSendToDevices(deviceInfos, payload);
+            expect(client.crypto.encryptAndSendToDevices).toHaveBeenLastCalledWith(deviceInfos, payload);
+        });
+    });
 });
@@ -15,6 +15,7 @@ limitations under the License.
 */

 import { MatrixEvent } from "../../../src";
+import { M_BEACON_INFO } from "../../../src/@types/beacon";
 import {
    isTimestampInDuration,
    Beacon,
@@ -129,6 +130,24 @@ describe('Beacon', () => {
            expect(beacon.beaconInfo).toBeTruthy();
        });

+        it('creates beacon without error from a malformed event', () => {
+            const event = new MatrixEvent({
+                type: M_BEACON_INFO.name,
+                room_id: roomId,
+                state_key: userId,
+                content: {},
+            });
+            const beacon = new Beacon(event);
+
+            expect(beacon.beaconInfoId).toEqual(event.getId());
+            expect(beacon.roomId).toEqual(roomId);
+            expect(beacon.isLive).toEqual(false);
+            expect(beacon.beaconInfoOwner).toEqual(userId);
+            expect(beacon.beaconInfoEventType).toEqual(liveBeaconEvent.getType());
+            expect(beacon.identifier).toEqual(`${roomId}_${userId}`);
+            expect(beacon.beaconInfo).toBeTruthy();
+        });
+
        describe('isLive()', () => {
            it('returns false when beacon is explicitly set to not live', () => {
                const beacon = new Beacon(notLiveBeaconEvent);
@@ -1,15 +1,15 @@
 import * as utils from "../test-utils/test-utils";
 import { PushProcessor } from "../../src/pushprocessor";
-import { EventType } from "../../src";
+import { EventType, MatrixClient, MatrixEvent } from "../../src";

 describe('NotificationService', function() {
    const testUserId = "@ali:matrix.org";
    const testDisplayName = "Alice M";
    const testRoomId = "!fl1bb13:localhost";

-    let testEvent;
+    let testEvent: MatrixEvent;

-    let pushProcessor;
+    let pushProcessor: PushProcessor;

    // These would be better if individual rules were configured in the tests themselves.
    const matrixClient = {
@@ -196,7 +196,7 @@ describe('NotificationService', function() {
                ],
            },
        },
-    };
+    } as unknown as MatrixClient;

    beforeEach(function() {
        testEvent = utils.mkEvent({
@@ -0,0 +1,349 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import MockHttpBackend from 'matrix-mock-request';
+import { indexedDB as fakeIndexedDB } from 'fake-indexeddb';
+
+import { IHttpOpts, IndexedDBStore, MatrixEvent, MemoryStore, Room } from "../../src";
+import { MatrixClient } from "../../src/client";
+import { ToDeviceBatch } from '../../src/models/ToDeviceMessage';
+import { logger } from '../../src/logger';
+import { IStore } from '../../src/store';
+
+const FAKE_USER = "@alice:example.org";
+const FAKE_DEVICE_ID = "AAAAAAAA";
+const FAKE_PAYLOAD = {
+    "foo": 42,
+};
+const EXPECTED_BODY = {
+    messages: {
+        [FAKE_USER]: {
+            [FAKE_DEVICE_ID]: FAKE_PAYLOAD,
+        },
+    },
+};
+
+const FAKE_MSG = {
+    userId: FAKE_USER,
+    deviceId: FAKE_DEVICE_ID,
+    payload: FAKE_PAYLOAD,
+};
+
+enum StoreType {
+    Memory = 'Memory',
+    IndexedDB = 'IndexedDB',
+}
+
+// Jest now uses @sinonjs/fake-timers which exposes tickAsync() and a number of
+// other async methods which break the event loop, letting scheduled promise
+// callbacks run. Unfortunately, Jest doesn't expose these, so we have to do
+// it manually (this is what sinon does under the hood). We do both in a loop
+// until the thing we expect happens: hopefully this is the least flakey way
+// and avoids assuming anything about the app's behaviour.
+const realSetTimeout = setTimeout;
+function flushPromises() {
+    return new Promise(r => {
+        realSetTimeout(r, 1);
+    });
+}
+
+async function flushAndRunTimersUntil(cond: () => boolean) {
+    while (!cond()) {
+        await flushPromises();
+        if (cond()) break;
+        jest.advanceTimersToNextTimer();
+    }
+}
+
+describe.each([
+    [StoreType.Memory], [StoreType.IndexedDB],
+])("queueToDevice (%s store)", function(storeType) {
+    let httpBackend: MockHttpBackend;
+    let client: MatrixClient;
+
+    beforeEach(async function() {
+        httpBackend = new MockHttpBackend();
+
+        let store: IStore;
+        if (storeType === StoreType.IndexedDB) {
+            const idbStore = new IndexedDBStore({ indexedDB: fakeIndexedDB });
+            await idbStore.startup();
+            store = idbStore;
+        } else {
+            store = new MemoryStore();
+        }
+
+        client = new MatrixClient({
+            baseUrl: "https://my.home.server",
+            accessToken: "my.access.token",
+            request: httpBackend.requestFn as IHttpOpts["request"],
+            store,
+        });
+    });
+
+    afterEach(function() {
+        jest.useRealTimers();
+        client.stopClient();
+    });
+
+    it("sends a to-device message", async function() {
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).check((request) => {
+            expect(request.data).toEqual(EXPECTED_BODY);
+        }).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+
+        await httpBackend.flushAllExpected();
+        // let the code handle the response to the request so we don't get
+        // log output after the test has finished (apparently stopping the
+        // client in aftereach is not sufficient.)
+        await flushPromises();
+    });
+
+    it("retries on error", async function() {
+        jest.useFakeTimers();
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(500);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).check((request) => {
+            expect(request.data).toEqual(EXPECTED_BODY);
+        }).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+        expect(httpBackend.flushSync(null, 1)).toEqual(1);
+
+        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+
+        expect(httpBackend.flushSync(null, 1)).toEqual(1);
+
+        // flush, as per comment in first test
+        await flushPromises();
+    });
+
+    it("stops retrying on 4xx errors", async function() {
+        jest.useFakeTimers();
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(400);
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+        expect(httpBackend.flushSync(null, 1)).toEqual(1);
+
+        // Asserting that another request is never made is obviously
+        // a bit tricky - we just flush the queue what should hopefully
+        // be plenty of times and assert that nothing comes through.
+        let tries = 0;
+        await flushAndRunTimersUntil(() => ++tries === 10);
+
+        expect(httpBackend.requests.length).toEqual(0);
+    });
+
+    it("honours ratelimiting", async function() {
+        jest.useFakeTimers();
+
+        // pick something obscure enough it's unlikley to clash with a
+        // retry delay the algorithm uses anyway
+        const retryDelay = 279 * 1000;
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(429, {
+            errcode: "M_LIMIT_EXCEEDED",
+            retry_after_ms: retryDelay,
+        });
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+        expect(httpBackend.flushSync(null, 1)).toEqual(1);
+        await flushPromises();
+
+        logger.info("Advancing clock to just before expected retry time...");
+
+        jest.advanceTimersByTime(retryDelay - 1000);
+        await flushPromises();
+
+        expect(httpBackend.requests.length).toEqual(0);
+
+        logger.info("Advancing clock past expected retry time...");
+
+        jest.advanceTimersByTime(2000);
+        await flushPromises();
+
+        expect(httpBackend.flushSync(null, 1)).toEqual(1);
+    });
+
+    it("retries on retryImmediately()", async function() {
+        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+            versions: ["r0.0.1"],
+        });
+
+        await Promise.all([client.startClient(), httpBackend.flush(null, 1, 20)]);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(500);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+        expect(await httpBackend.flush(null, 1, 1)).toEqual(1);
+        await flushPromises();
+
+        client.retryImmediately();
+
+        // longer timeout here to try & avoid flakiness
+        expect(await httpBackend.flush(null, 1, 3000)).toEqual(1);
+    });
+
+    it("retries on when client is started", async function() {
+        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+            versions: ["r0.0.1"],
+        });
+
+        await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(500);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+        expect(await httpBackend.flush(null, 1, 1)).toEqual(1);
+        await flushPromises();
+
+        client.stopClient();
+        await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
+
+        expect(await httpBackend.flush(null, 1, 20)).toEqual(1);
+    });
+
+    it("retries when a message is retried", async function() {
+        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+            versions: ["r0.0.1"],
+        });
+
+        await Promise.all([client.startClient(), httpBackend.flush(null, 1, 20)]);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(500);
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).respond(200, {});
+
+        await client.queueToDevice({
+            eventType: "org.example.foo",
+            batch: [
+                FAKE_MSG,
+            ],
+        });
+
+        expect(await httpBackend.flush(null, 1, 1)).toEqual(1);
+        await flushPromises();
+
+        const dummyEvent = new MatrixEvent({
+            event_id: "!fake:example.org",
+        });
+        const mockRoom = {
+            updatePendingEvent: jest.fn(),
+        } as unknown as Room;
+        client.resendEvent(dummyEvent, mockRoom);
+
+        expect(await httpBackend.flush(null, 1, 20)).toEqual(1);
+    });
+
+    it("splits many messages into multiple HTTP requests", async function() {
+        const batch: ToDeviceBatch = {
+            eventType: "org.example.foo",
+            batch: [],
+        };
+
+        for (let i = 0; i <= 20; ++i) {
+            batch.batch.push({
+                userId: `@user${i}:example.org`,
+                deviceId: FAKE_DEVICE_ID,
+                payload: FAKE_PAYLOAD,
+            });
+        }
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).check((request) => {
+            expect(Object.keys(request.data.messages).length).toEqual(20);
+        }).respond(200, {});
+
+        httpBackend.when(
+            "PUT", "/sendToDevice/org.example.foo/",
+        ).check((request) => {
+            expect(Object.keys(request.data.messages).length).toEqual(1);
+        }).respond(200, {});
+
+        await client.queueToDevice(batch);
+        await httpBackend.flushAllExpected();
+
+        // flush, as per comment in first test
+        await flushPromises();
+    });
+});
@@ -21,7 +21,7 @@ describe("realtime-callbacks", function() {

        it("should default to a zero timeout", function() {
            const callback = jest.fn();
-            callbacks.setTimeout(callback);
+            callbacks.setTimeout(callback, 0);

            expect(callback).not.toHaveBeenCalled();
            tick(0);
@@ -38,11 +38,11 @@ describe("realtime-callbacks", function() {
        it("should set 'this' to the global object", function() {
            let passed = false;
            const callback = function() {
-                expect(this).toBe(global); // eslint-disable-line @babel/no-invalid-this
-                expect(this.console).toBeTruthy(); // eslint-disable-line @babel/no-invalid-this
+                expect(this).toBe(global); // eslint-disable-line @typescript-eslint/no-invalid-this
+                expect(this.console).toBeTruthy(); // eslint-disable-line @typescript-eslint/no-invalid-this
                passed = true;
            };
-            callbacks.setTimeout(callback);
+            callbacks.setTimeout(callback, 0);
            tick(0);
            expect(passed).toBe(true);
        });
@@ -92,7 +92,7 @@ describe("realtime-callbacks", function() {
                expect(callback2).not.toHaveBeenCalled();
            });

-            callbacks.setTimeout(callback1);
+            callbacks.setTimeout(callback1, 0);
            callbacks.setTimeout(callback2, -100);

            expect(callback1).not.toHaveBeenCalled();
@@ -109,14 +109,14 @@ describe("realtime-callbacks", function() {
                expect(callback2).not.toHaveBeenCalled();
            });

-            callbacks.setTimeout(callback1);
+            callbacks.setTimeout(callback1, 1);
            expect(callback1).not.toHaveBeenCalled();
            expect(callback2).not.toHaveBeenCalled();
-            tick(0);
+            tick(1);
            expect(callback1).toHaveBeenCalled();
            // the fake timer won't actually run callbacks registered during
            // one tick until the next tick.
-            tick(1);
+            tick(2);
            expect(callback2).toHaveBeenCalled();
        });

@@ -139,9 +139,9 @@ describe("realtime-callbacks", function() {
    describe("cancelTimeout", function() {
        it("should cancel a pending timeout", function() {
            const callback = jest.fn();
-            const k = callbacks.setTimeout(callback);
+            const k = callbacks.setTimeout(callback, 10);
            callbacks.clearTimeout(k);
-            tick(0);
+            tick(11);
            expect(callback).not.toHaveBeenCalled();
        });

@@ -1,12 +1,29 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 import * as utils from "../test-utils/test-utils";
-import { RoomMember } from "../../src/models/room-member";
+import { RoomMember, RoomMemberEvent } from "../../src/models/room-member";
+import { RoomState } from "../../src";

 describe("RoomMember", function() {
    const roomId = "!foo:bar";
    const userA = "@alice:bar";
    const userB = "@bertha:bar";
    const userC = "@clarissa:bar";
-    let member;
+    let member = new RoomMember(roomId, userA);

    beforeEach(function() {
        member = new RoomMember(roomId, userA);
@@ -27,17 +44,17 @@ describe("RoomMember", function() {
                    avatar_url: "mxc://flibble/wibble",
                },
            });
-            const url = member.getAvatarUrl(hsUrl);
+            const url = member.getAvatarUrl(hsUrl, 1, 1, '', false, false);
            // we don't care about how the mxc->http conversion is done, other
            // than it contains the mxc body.
-            expect(url.indexOf("flibble/wibble")).not.toEqual(-1);
+            expect(url?.indexOf("flibble/wibble")).not.toEqual(-1);
        });

        it("should return nothing if there is no m.room.member and allowDefault=false",
-        function() {
-            const url = member.getAvatarUrl(hsUrl, 64, 64, "crop", false);
-            expect(url).toEqual(null);
-        });
+            function() {
+                const url = member.getAvatarUrl(hsUrl, 64, 64, "crop", false, false);
+                expect(url).toEqual(null);
+            });
    });

    describe("setPowerLevelEvent", function() {
@@ -66,92 +83,92 @@ describe("RoomMember", function() {
        });

        it("should emit 'RoomMember.powerLevel' if the power level changes.",
-        function() {
-            const event = utils.mkEvent({
-                type: "m.room.power_levels",
-                room: roomId,
-                user: userA,
-                content: {
-                    users_default: 20,
-                    users: {
-                        "@bertha:bar": 200,
-                        "@invalid:user": 10,  // shouldn't barf on this.
+            function() {
+                const event = utils.mkEvent({
+                    type: "m.room.power_levels",
+                    room: roomId,
+                    user: userA,
+                    content: {
+                        users_default: 20,
+                        users: {
+                            "@bertha:bar": 200,
+                            "@invalid:user": 10,  // shouldn't barf on this.
+                        },
                    },
-                },
-                event: true,
-            });
-            let emitCount = 0;
+                    event: true,
+                });
+                let emitCount = 0;

-            member.on("RoomMember.powerLevel", function(emitEvent, emitMember) {
-                emitCount += 1;
-                expect(emitMember).toEqual(member);
-                expect(emitEvent).toEqual(event);
-            });
+                member.on(RoomMemberEvent.PowerLevel, function(emitEvent, emitMember) {
+                    emitCount += 1;
+                    expect(emitMember).toEqual(member);
+                    expect(emitEvent).toEqual(event);
+                });

-            member.setPowerLevelEvent(event);
-            expect(emitCount).toEqual(1);
-            member.setPowerLevelEvent(event); // no-op
-            expect(emitCount).toEqual(1);
-        });
+                member.setPowerLevelEvent(event);
+                expect(emitCount).toEqual(1);
+                member.setPowerLevelEvent(event); // no-op
+                expect(emitCount).toEqual(1);
+            });

        it("should honour power levels of zero.",
-        function() {
-            const event = utils.mkEvent({
-                type: "m.room.power_levels",
-                room: roomId,
-                user: userA,
-                content: {
-                    users_default: 20,
-                    users: {
-                        "@alice:bar": 0,
+            function() {
+                const event = utils.mkEvent({
+                    type: "m.room.power_levels",
+                    room: roomId,
+                    user: userA,
+                    content: {
+                        users_default: 20,
+                        users: {
+                            "@alice:bar": 0,
+                        },
                    },
-                },
-                event: true,
-            });
-            let emitCount = 0;
+                    event: true,
+                });
+                let emitCount = 0;

-            // set the power level to something other than zero or we
-            // won't get an event
-            member.powerLevel = 1;
-            member.on("RoomMember.powerLevel", function(emitEvent, emitMember) {
-                emitCount += 1;
-                expect(emitMember.userId).toEqual('@alice:bar');
-                expect(emitMember.powerLevel).toEqual(0);
-                expect(emitEvent).toEqual(event);
-            });
+                // set the power level to something other than zero or we
+                // won't get an event
+                member.powerLevel = 1;
+                member.on(RoomMemberEvent.PowerLevel, function(emitEvent, emitMember) {
+                    emitCount += 1;
+                    expect(emitMember.userId).toEqual('@alice:bar');
+                    expect(emitMember.powerLevel).toEqual(0);
+                    expect(emitEvent).toEqual(event);
+                });

-            member.setPowerLevelEvent(event);
-            expect(member.powerLevel).toEqual(0);
-            expect(emitCount).toEqual(1);
-        });
+                member.setPowerLevelEvent(event);
+                expect(member.powerLevel).toEqual(0);
+                expect(emitCount).toEqual(1);
+            });

        it("should not honor string power levels.",
-        function() {
-            const event = utils.mkEvent({
-                type: "m.room.power_levels",
-                room: roomId,
-                user: userA,
-                content: {
-                    users_default: 20,
-                    users: {
-                        "@alice:bar": "5",
+            function() {
+                const event = utils.mkEvent({
+                    type: "m.room.power_levels",
+                    room: roomId,
+                    user: userA,
+                    content: {
+                        users_default: 20,
+                        users: {
+                            "@alice:bar": "5",
+                        },
                    },
-                },
-                event: true,
-            });
-            let emitCount = 0;
+                    event: true,
+                });
+                let emitCount = 0;

-            member.on("RoomMember.powerLevel", function(emitEvent, emitMember) {
-                emitCount += 1;
-                expect(emitMember.userId).toEqual('@alice:bar');
-                expect(emitMember.powerLevel).toEqual(20);
-                expect(emitEvent).toEqual(event);
-            });
+                member.on(RoomMemberEvent.PowerLevel, function(emitEvent, emitMember) {
+                    emitCount += 1;
+                    expect(emitMember.userId).toEqual('@alice:bar');
+                    expect(emitMember.powerLevel).toEqual(20);
+                    expect(emitEvent).toEqual(event);
+                });

-            member.setPowerLevelEvent(event);
-            expect(member.powerLevel).toEqual(20);
-            expect(emitCount).toEqual(1);
-        });
+                member.setPowerLevelEvent(event);
+                expect(member.powerLevel).toEqual(20);
+                expect(emitCount).toEqual(1);
+            });
    });

    describe("setTypingEvent", function() {
@@ -183,34 +200,34 @@ describe("RoomMember", function() {
        });

        it("should emit 'RoomMember.typing' if the typing state changes",
-        function() {
-            const event = utils.mkEvent({
-                type: "m.typing",
-                room: roomId,
-                content: {
-                    user_ids: [
-                        userA, userC,
-                    ],
-                },
-                event: true,
+            function() {
+                const event = utils.mkEvent({
+                    type: "m.typing",
+                    room: roomId,
+                    content: {
+                        user_ids: [
+                            userA, userC,
+                        ],
+                    },
+                    event: true,
+                });
+                let emitCount = 0;
+                member.on(RoomMemberEvent.Typing, function(ev, mem) {
+                    expect(mem).toEqual(member);
+                    expect(ev).toEqual(event);
+                    emitCount += 1;
+                });
+                member.typing = false;
+                member.setTypingEvent(event);
+                expect(emitCount).toEqual(1);
+                member.setTypingEvent(event); // no-op
+                expect(emitCount).toEqual(1);
            });
-            let emitCount = 0;
-            member.on("RoomMember.typing", function(ev, mem) {
-                expect(mem).toEqual(member);
-                expect(ev).toEqual(event);
-                emitCount += 1;
-            });
-            member.typing = false;
-            member.setTypingEvent(event);
-            expect(emitCount).toEqual(1);
-            member.setTypingEvent(event); // no-op
-            expect(emitCount).toEqual(1);
-        });
    });

    describe("isOutOfBand", function() {
        it("should be set by markOutOfBand", function() {
-            const member = new RoomMember();
+            const member = new RoomMember(roomId, userA);
            expect(member.isOutOfBand()).toEqual(false);
            member.markOutOfBand();
            expect(member.isOutOfBand()).toEqual(true);
@@ -235,50 +252,50 @@ describe("RoomMember", function() {
        });

        it("should set 'membership' and assign the event to 'events.member'.",
-        function() {
-            member.setMembershipEvent(inviteEvent);
-            expect(member.membership).toEqual("invite");
-            expect(member.events.member).toEqual(inviteEvent);
-            member.setMembershipEvent(joinEvent);
-            expect(member.membership).toEqual("join");
-            expect(member.events.member).toEqual(joinEvent);
-        });
+            function() {
+                member.setMembershipEvent(inviteEvent);
+                expect(member.membership).toEqual("invite");
+                expect(member.events.member).toEqual(inviteEvent);
+                member.setMembershipEvent(joinEvent);
+                expect(member.membership).toEqual("join");
+                expect(member.events.member).toEqual(joinEvent);
+            });

        it("should set 'name' based on user_id, displayname and room state",
-        function() {
-            const roomState = {
-                getStateEvents: function(type) {
-                    if (type !== "m.room.member") {
-                        return [];
-                    }
-                    return [
-                        utils.mkMembership({
-                            event: true, mship: "join", room: roomId,
-                            user: userB,
-                        }),
-                        utils.mkMembership({
-                            event: true, mship: "join", room: roomId,
-                            user: userC, name: "Alice",
-                        }),
-                        joinEvent,
-                    ];
-                },
-                getUserIdsWithDisplayName: function(displayName) {
-                    return [userA, userC];
-                },
-            };
-            expect(member.name).toEqual(userA); // default = user_id
-            member.setMembershipEvent(joinEvent);
-            expect(member.name).toEqual("Alice"); // prefer displayname
-            member.setMembershipEvent(joinEvent, roomState);
-            expect(member.name).not.toEqual("Alice"); // it should disambig.
-            // user_id should be there somewhere
-            expect(member.name.indexOf(userA)).not.toEqual(-1);
-        });
+            function() {
+                const roomState = {
+                    getStateEvents: function(type) {
+                        if (type !== "m.room.member") {
+                            return [];
+                        }
+                        return [
+                            utils.mkMembership({
+                                event: true, mship: "join", room: roomId,
+                                user: userB,
+                            }),
+                            utils.mkMembership({
+                                event: true, mship: "join", room: roomId,
+                                user: userC, name: "Alice",
+                            }),
+                            joinEvent,
+                        ];
+                    },
+                    getUserIdsWithDisplayName: function(displayName) {
+                        return [userA, userC];
+                    },
+                } as unknown as RoomState;
+                expect(member.name).toEqual(userA); // default = user_id
+                member.setMembershipEvent(joinEvent);
+                expect(member.name).toEqual("Alice"); // prefer displayname
+                member.setMembershipEvent(joinEvent, roomState);
+                expect(member.name).not.toEqual("Alice"); // it should disambig.
+                // user_id should be there somewhere
+                expect(member.name.indexOf(userA)).not.toEqual(-1);
+            });

        it("should emit 'RoomMember.membership' if the membership changes", function() {
            let emitCount = 0;
-            member.on("RoomMember.membership", function(ev, mem) {
+            member.on(RoomMemberEvent.Membership, function(ev, mem) {
                emitCount += 1;
                expect(mem).toEqual(member);
                expect(ev).toEqual(inviteEvent);
@@ -291,7 +308,7 @@ describe("RoomMember", function() {

        it("should emit 'RoomMember.name' if the name changes", function() {
            let emitCount = 0;
-            member.on("RoomMember.name", function(ev, mem) {
+            member.on(RoomMemberEvent.Name, function(ev, mem) {
                emitCount += 1;
                expect(mem).toEqual(member);
                expect(ev).toEqual(joinEvent);
@@ -341,7 +358,7 @@ describe("RoomMember", function() {
                getUserIdsWithDisplayName: function(displayName) {
                    return [userA, userC];
                },
-            };
+            } as unknown as RoomState;
            expect(member.name).toEqual(userA); // default = user_id
            member.setMembershipEvent(joinEvent, roomState);
            expect(member.name).not.toEqual("Alíce"); // it should disambig.
@@ -1,14 +1,37 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { MockedObject } from 'jest-mock';
+
 import * as utils from "../test-utils/test-utils";
 import { makeBeaconEvent, makeBeaconInfoEvent } from "../test-utils/beacon";
 import { filterEmitCallsByEventType } from "../test-utils/emitter";
 import { RoomState, RoomStateEvent } from "../../src/models/room-state";
-import { BeaconEvent, getBeaconInfoIdentifier } from "../../src/models/beacon";
+import {
+    Beacon,
+    BeaconEvent,
+    getBeaconInfoIdentifier,
+} from "../../src/models/beacon";
 import { EventType, RelationType, UNSTABLE_MSC2716_MARKER } from "../../src/@types/event";
 import {
    MatrixEvent,
    MatrixEventEvent,
 } from "../../src/models/event";
 import { M_BEACON } from "../../src/@types/beacon";
+import { MatrixClient } from "../../src/client";

 describe("RoomState", function() {
    const roomId = "!foo:bar";
@@ -17,7 +40,7 @@ describe("RoomState", function() {
    const userC = "@cleo:bar";
    const userLazy = "@lazy:bar";

-    let state;
+    let state = new RoomState(roomId);

    beforeEach(function() {
        state = new RoomState(roomId);
@@ -67,8 +90,8 @@ describe("RoomState", function() {

        it("should return a member which changes as state changes", function() {
            const member = state.getMember(userB);
-            expect(member.membership).toEqual("join");
-            expect(member.name).toEqual(userB);
+            expect(member?.membership).toEqual("join");
+            expect(member?.name).toEqual(userB);

            state.setStateEvents([
                utils.mkMembership({
@@ -77,40 +100,40 @@ describe("RoomState", function() {
                }),
            ]);

-            expect(member.membership).toEqual("leave");
-            expect(member.name).toEqual("BobGone");
+            expect(member?.membership).toEqual("leave");
+            expect(member?.name).toEqual("BobGone");
        });
    });

    describe("getSentinelMember", function() {
        it("should return a member with the user id as name", function() {
-            expect(state.getSentinelMember("@no-one:here").name).toEqual("@no-one:here");
+            expect(state.getSentinelMember("@no-one:here")?.name).toEqual("@no-one:here");
        });

        it("should return a member which doesn't change when the state is updated",
-        function() {
-            const preLeaveUser = state.getSentinelMember(userA);
-            state.setStateEvents([
-                utils.mkMembership({
-                    room: roomId, user: userA, mship: "leave", event: true,
-                    name: "AliceIsGone",
-                }),
-            ]);
-            const postLeaveUser = state.getSentinelMember(userA);
+            function() {
+                const preLeaveUser = state.getSentinelMember(userA);
+                state.setStateEvents([
+                    utils.mkMembership({
+                        room: roomId, user: userA, mship: "leave", event: true,
+                        name: "AliceIsGone",
+                    }),
+                ]);
+                const postLeaveUser = state.getSentinelMember(userA);

-            expect(preLeaveUser.membership).toEqual("join");
-            expect(preLeaveUser.name).toEqual(userA);
+                expect(preLeaveUser?.membership).toEqual("join");
+                expect(preLeaveUser?.name).toEqual(userA);

-            expect(postLeaveUser.membership).toEqual("leave");
-            expect(postLeaveUser.name).toEqual("AliceIsGone");
-        });
+                expect(postLeaveUser?.membership).toEqual("leave");
+                expect(postLeaveUser?.name).toEqual("AliceIsGone");
+            });
    });

    describe("getStateEvents", function() {
        it("should return null if a state_key was specified and there was no match",
-        function() {
-            expect(state.getStateEvents("foo.bar.baz", "keyname")).toEqual(null);
-        });
+            function() {
+                expect(state.getStateEvents("foo.bar.baz", "keyname")).toEqual(null);
+            });

        it("should return an empty list if a state_key was not specified and there" +
            " was no match", function() {
@@ -118,21 +141,21 @@ describe("RoomState", function() {
        });

        it("should return a list of matching events if no state_key was specified",
-        function() {
-            const events = state.getStateEvents("m.room.member");
-            expect(events.length).toEqual(2);
-            // ordering unimportant
-            expect([userA, userB].indexOf(events[0].getStateKey())).not.toEqual(-1);
-            expect([userA, userB].indexOf(events[1].getStateKey())).not.toEqual(-1);
-        });
+            function() {
+                const events = state.getStateEvents("m.room.member");
+                expect(events.length).toEqual(2);
+                // ordering unimportant
+                expect([userA, userB].indexOf(events[0].getStateKey() as string)).not.toEqual(-1);
+                expect([userA, userB].indexOf(events[1].getStateKey() as string)).not.toEqual(-1);
+            });

        it("should return a single MatrixEvent if a state_key was specified",
-        function() {
-            const event = state.getStateEvents("m.room.member", userA);
-            expect(event.getContent()).toMatchObject({
-                membership: "join",
+            function() {
+                const event = state.getStateEvents("m.room.member", userA);
+                expect(event.getContent()).toMatchObject({
+                    membership: "join",
+                });
            });
-        });
    });

    describe("setStateEvents", function() {
@@ -146,7 +169,7 @@ describe("RoomState", function() {
                }),
            ];
            let emitCount = 0;
-            state.on("RoomState.members", function(ev, st, mem) {
+            state.on(RoomStateEvent.Members, function(ev, st, mem) {
                expect(ev).toEqual(memberEvents[emitCount]);
                expect(st).toEqual(state);
                expect(mem).toEqual(state.getMember(ev.getSender()));
@@ -166,7 +189,7 @@ describe("RoomState", function() {
                }),
            ];
            let emitCount = 0;
-            state.on("RoomState.newMember", function(ev, st, mem) {
+            state.on(RoomStateEvent.NewMember, function(ev, st, mem) {
                expect(state.getMember(mem.userId)).toEqual(mem);
                expect(mem.userId).toEqual(memberEvents[emitCount].getSender());
                expect(mem.membership).toBeFalsy();  // not defined yet
@@ -192,7 +215,7 @@ describe("RoomState", function() {
                }),
            ];
            let emitCount = 0;
-            state.on("RoomState.events", function(ev, st) {
+            state.on(RoomStateEvent.Events, function(ev, st) {
                expect(ev).toEqual(events[emitCount]);
                expect(st).toEqual(state);
                emitCount += 1;
@@ -272,7 +295,7 @@ describe("RoomState", function() {
                }),
            ];
            let emitCount = 0;
-            state.on("RoomState.Marker", function(markerEvent, markerFoundOptions) {
+            state.on(RoomStateEvent.Marker, function(markerEvent, markerFoundOptions) {
                expect(markerEvent).toEqual(events[emitCount]);
                expect(markerFoundOptions).toEqual({ timelineWasEmpty: true });
                emitCount += 1;
@@ -296,7 +319,7 @@ describe("RoomState", function() {

            it('does not add redacted beacon info events to state', () => {
                const redactedBeaconEvent = makeBeaconInfoEvent(userA, roomId);
-                const redactionEvent = { event: { type: 'm.room.redaction' } };
+                const redactionEvent = new MatrixEvent({ type: 'm.room.redaction' });
                redactedBeaconEvent.makeRedacted(redactionEvent);
                const emitSpy = jest.spyOn(state, 'emit');

@@ -316,27 +339,27 @@ describe("RoomState", function() {

                state.setStateEvents([beaconEvent]);
                const beaconInstance = state.beacons.get(getBeaconInfoIdentifier(beaconEvent));
-                expect(beaconInstance.isLive).toEqual(true);
+                expect(beaconInstance?.isLive).toEqual(true);

                state.setStateEvents([updatedBeaconEvent]);

                // same Beacon
                expect(state.beacons.get(getBeaconInfoIdentifier(beaconEvent))).toBe(beaconInstance);
                // updated liveness
-                expect(state.beacons.get(getBeaconInfoIdentifier(beaconEvent)).isLive).toEqual(false);
+                expect(state.beacons.get(getBeaconInfoIdentifier(beaconEvent))?.isLive).toEqual(false);
            });

            it('destroys and removes redacted beacon events', () => {
                const beaconId = '$beacon1';
                const beaconEvent = makeBeaconInfoEvent(userA, roomId, { isLive: true }, beaconId);
                const redactedBeaconEvent = makeBeaconInfoEvent(userA, roomId, { isLive: true }, beaconId);
-                const redactionEvent = { event: { type: 'm.room.redaction', redacts: beaconEvent.getId() } };
+                const redactionEvent = new MatrixEvent({ type: 'm.room.redaction', redacts: beaconEvent.getId() });
                redactedBeaconEvent.makeRedacted(redactionEvent);

                state.setStateEvents([beaconEvent]);
                const beaconInstance = state.beacons.get(getBeaconInfoIdentifier(beaconEvent));
-                const destroySpy = jest.spyOn(beaconInstance, 'destroy');
-                expect(beaconInstance.isLive).toEqual(true);
+                const destroySpy = jest.spyOn(beaconInstance as Beacon, 'destroy');
+                expect(beaconInstance?.isLive).toEqual(true);

                state.setStateEvents([redactedBeaconEvent]);

@@ -357,7 +380,7 @@ describe("RoomState", function() {

                // live beacon is now not live
                const updatedLiveBeaconEvent = makeBeaconInfoEvent(
-                    userA, roomId, { isLive: false }, liveBeaconEvent.getId(), '$beacon1',
+                    userA, roomId, { isLive: false }, liveBeaconEvent.getId(),
                );

                state.setStateEvents([updatedLiveBeaconEvent]);
@@ -377,8 +400,8 @@ describe("RoomState", function() {
            state.markOutOfBandMembersStarted();
            state.setOutOfBandMembers([oobMemberEvent]);
            const member = state.getMember(userLazy);
-            expect(member.userId).toEqual(userLazy);
-            expect(member.isOutOfBand()).toEqual(true);
+            expect(member?.userId).toEqual(userLazy);
+            expect(member?.isOutOfBand()).toEqual(true);
        });

        it("should have no effect when not in correct status", function() {
@@ -394,7 +417,7 @@ describe("RoomState", function() {
                user: userLazy, mship: "join", room: roomId, event: true,
            });
            let eventReceived = false;
-            state.once('RoomState.newMember', (_, __, member) => {
+            state.once(RoomStateEvent.NewMember, (_event, _state, member) => {
                expect(member.userId).toEqual(userLazy);
                eventReceived = true;
            });
@@ -410,8 +433,8 @@ describe("RoomState", function() {
            state.markOutOfBandMembersStarted();
            state.setOutOfBandMembers([oobMemberEvent]);
            const memberA = state.getMember(userA);
-            expect(memberA.events.member.getId()).not.toEqual(oobMemberEvent.getId());
-            expect(memberA.isOutOfBand()).toEqual(false);
+            expect(memberA?.events?.member?.getId()).not.toEqual(oobMemberEvent.getId());
+            expect(memberA?.isOutOfBand()).toEqual(false);
        });

        it("should emit members when updating a member", function() {
@@ -420,7 +443,7 @@ describe("RoomState", function() {
                user: doesntExistYetUserId, mship: "join", room: roomId, event: true,
            });
            let eventReceived = false;
-            state.once('RoomState.members', (_, __, member) => {
+            state.once(RoomStateEvent.Members, (_event, _state, member) => {
                expect(member.userId).toEqual(doesntExistYetUserId);
                eventReceived = true;
            });
@@ -443,8 +466,8 @@ describe("RoomState", function() {
            [userA, userB, userLazy].forEach((userId) => {
                const member = state.getMember(userId);
                const memberCopy = copy.getMember(userId);
-                expect(member.name).toEqual(memberCopy.name);
-                expect(member.isOutOfBand()).toEqual(memberCopy.isOutOfBand());
+                expect(member?.name).toEqual(memberCopy?.name);
+                expect(member?.isOutOfBand()).toEqual(memberCopy?.isOutOfBand());
            });
            // check member keys
            expect(Object.keys(state.members)).toEqual(Object.keys(copy.members));
@@ -496,78 +519,80 @@ describe("RoomState", function() {

    describe("maySendStateEvent", function() {
        it("should say any member may send state with no power level event",
-        function() {
-            expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
-        });
+            function() {
+                expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
+            });

        it("should say members with power >=50 may send state with power level event " +
        "but no state default",
        function() {
-            const powerLevelEvent = {
-                type: "m.room.power_levels", room: roomId, user: userA, event: true,
+            const powerLevelEvent = new MatrixEvent({
+                type: "m.room.power_levels", room_id: roomId, sender: userA,
+                state_key: "",
                content: {
                    users_default: 10,
                    // state_default: 50, "intentionally left blank"
                    events_default: 25,
                    users: {
+                        [userA]: 50,
                    },
                },
-            };
-            powerLevelEvent.content.users[userA] = 50;
+            });

-            state.setStateEvents([utils.mkEvent(powerLevelEvent)]);
+            state.setStateEvents([powerLevelEvent]);

            expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
            expect(state.maySendStateEvent('m.room.name', userB)).toEqual(false);
        });

        it("should obey state_default",
-        function() {
-            const powerLevelEvent = {
-                type: "m.room.power_levels", room: roomId, user: userA, event: true,
-                content: {
-                    users_default: 10,
-                    state_default: 30,
-                    events_default: 25,
-                    users: {
+            function() {
+                const powerLevelEvent = new MatrixEvent({
+                    type: "m.room.power_levels", room_id: roomId, sender: userA,
+                    state_key: "",
+                    content: {
+                        users_default: 10,
+                        state_default: 30,
+                        events_default: 25,
+                        users: {
+                            [userA]: 30,
+                            [userB]: 29,
+                        },
                    },
-                },
-            };
-            powerLevelEvent.content.users[userA] = 30;
-            powerLevelEvent.content.users[userB] = 29;
+                });

-            state.setStateEvents([utils.mkEvent(powerLevelEvent)]);
+                state.setStateEvents([powerLevelEvent]);

-            expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
-            expect(state.maySendStateEvent('m.room.name', userB)).toEqual(false);
-        });
+                expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
+                expect(state.maySendStateEvent('m.room.name', userB)).toEqual(false);
+            });

        it("should honour explicit event power levels in the power_levels event",
-        function() {
-            const powerLevelEvent = {
-                type: "m.room.power_levels", room: roomId, user: userA, event: true,
-                content: {
-                    events: {
-                        "m.room.other_thing": 76,
+            function() {
+                const powerLevelEvent = new MatrixEvent({
+                    type: "m.room.power_levels", room_id: roomId, sender: userA,
+                    state_key: "", content: {
+                        events: {
+                            "m.room.other_thing": 76,
+                        },
+                        users_default: 10,
+                        state_default: 50,
+                        events_default: 25,
+                        users: {
+                            [userA]: 80,
+                            [userB]: 50,
+                        },
                    },
-                    users_default: 10,
-                    state_default: 50,
-                    events_default: 25,
-                    users: {
-                    },
-                },
-            };
-            powerLevelEvent.content.users[userA] = 80;
-            powerLevelEvent.content.users[userB] = 50;
+                });

-            state.setStateEvents([utils.mkEvent(powerLevelEvent)]);
+                state.setStateEvents([powerLevelEvent]);

-            expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
-            expect(state.maySendStateEvent('m.room.name', userB)).toEqual(true);
+                expect(state.maySendStateEvent('m.room.name', userA)).toEqual(true);
+                expect(state.maySendStateEvent('m.room.name', userB)).toEqual(true);

-            expect(state.maySendStateEvent('m.room.other_thing', userA)).toEqual(true);
-            expect(state.maySendStateEvent('m.room.other_thing', userB)).toEqual(false);
-        });
+                expect(state.maySendStateEvent('m.room.other_thing', userA)).toEqual(true);
+                expect(state.maySendStateEvent('m.room.other_thing', userB)).toEqual(false);
+            });
    });

    describe("getJoinedMemberCount", function() {
@@ -682,71 +707,73 @@ describe("RoomState", function() {

    describe("maySendEvent", function() {
        it("should say any member may send events with no power level event",
-        function() {
-            expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
-            expect(state.maySendMessage(userA)).toEqual(true);
-        });
+            function() {
+                expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
+                expect(state.maySendMessage(userA)).toEqual(true);
+            });

        it("should obey events_default",
-        function() {
-            const powerLevelEvent = {
-                type: "m.room.power_levels", room: roomId, user: userA, event: true,
-                content: {
-                    users_default: 10,
-                    state_default: 30,
-                    events_default: 25,
-                    users: {
+            function() {
+                const powerLevelEvent = new MatrixEvent({
+                    type: "m.room.power_levels", room_id: roomId, sender: userA,
+                    state_key: "",
+                    content: {
+                        users_default: 10,
+                        state_default: 30,
+                        events_default: 25,
+                        users: {
+                            [userA]: 26,
+                            [userB]: 24,
+                        },
                    },
-                },
-            };
-            powerLevelEvent.content.users[userA] = 26;
-            powerLevelEvent.content.users[userB] = 24;
+                });

-            state.setStateEvents([utils.mkEvent(powerLevelEvent)]);
+                state.setStateEvents([powerLevelEvent]);

-            expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
-            expect(state.maySendEvent('m.room.message', userB)).toEqual(false);
+                expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
+                expect(state.maySendEvent('m.room.message', userB)).toEqual(false);

-            expect(state.maySendMessage(userA)).toEqual(true);
-            expect(state.maySendMessage(userB)).toEqual(false);
-        });
+                expect(state.maySendMessage(userA)).toEqual(true);
+                expect(state.maySendMessage(userB)).toEqual(false);
+            });

        it("should honour explicit event power levels in the power_levels event",
-        function() {
-            const powerLevelEvent = {
-                type: "m.room.power_levels", room: roomId, user: userA, event: true,
-                content: {
-                    events: {
-                        "m.room.other_thing": 33,
+            function() {
+                const powerLevelEvent = new MatrixEvent({
+                    type: "m.room.power_levels", room_id: roomId, sender: userA,
+                    state_key: "",
+                    content: {
+                        events: {
+                            "m.room.other_thing": 33,
+                        },
+                        users_default: 10,
+                        state_default: 50,
+                        events_default: 25,
+                        users: {
+                            [userA]: 40,
+                            [userB]: 30,
+                        },
                    },
-                    users_default: 10,
-                    state_default: 50,
-                    events_default: 25,
-                    users: {
-                    },
-                },
-            };
-            powerLevelEvent.content.users[userA] = 40;
-            powerLevelEvent.content.users[userB] = 30;
+                });

-            state.setStateEvents([utils.mkEvent(powerLevelEvent)]);
+                state.setStateEvents([powerLevelEvent]);

-            expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
-            expect(state.maySendEvent('m.room.message', userB)).toEqual(true);
+                expect(state.maySendEvent('m.room.message', userA)).toEqual(true);
+                expect(state.maySendEvent('m.room.message', userB)).toEqual(true);

-            expect(state.maySendMessage(userA)).toEqual(true);
-            expect(state.maySendMessage(userB)).toEqual(true);
+                expect(state.maySendMessage(userA)).toEqual(true);
+                expect(state.maySendMessage(userB)).toEqual(true);

-            expect(state.maySendEvent('m.room.other_thing', userA)).toEqual(true);
-            expect(state.maySendEvent('m.room.other_thing', userB)).toEqual(false);
-        });
+                expect(state.maySendEvent('m.room.other_thing', userA)).toEqual(true);
+                expect(state.maySendEvent('m.room.other_thing', userB)).toEqual(false);
+            });
    });

    describe('processBeaconEvents', () => {
-        const beacon1 = makeBeaconInfoEvent(userA, roomId, {}, '$beacon1', '$beacon1');
-        const beacon2 = makeBeaconInfoEvent(userB, roomId, {}, '$beacon2', '$beacon2');
+        const beacon1 = makeBeaconInfoEvent(userA, roomId, {}, '$beacon1');
+        const beacon2 = makeBeaconInfoEvent(userB, roomId, {}, '$beacon2');

-        const mockClient = { decryptEventIfNeeded: jest.fn() };
+        const mockClient = { decryptEventIfNeeded: jest.fn() } as unknown as MockedObject<MatrixClient>;

        beforeEach(() => {
            mockClient.decryptEventIfNeeded.mockClear();
@@ -816,11 +843,11 @@ describe("RoomState", function() {
                    beaconInfoId: 'some-other-beacon',
                });

-                state.setStateEvents([beacon1, beacon2], mockClient);
+                state.setStateEvents([beacon1, beacon2]);

                expect(state.beacons.size).toEqual(2);

-                const beaconInstance = state.beacons.get(getBeaconInfoIdentifier(beacon1));
+                const beaconInstance = state.beacons.get(getBeaconInfoIdentifier(beacon1)) as Beacon;
                const addLocationsSpy = jest.spyOn(beaconInstance, 'addLocations');

                state.processBeaconEvents([location1, location2, location3], mockClient);
@@ -885,7 +912,7 @@ describe("RoomState", function() {
                });
                state.setStateEvents([beacon1, beacon2]);

-                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1));
+                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1)) as Beacon;
                const addLocationsSpy = jest.spyOn(beacon, 'addLocations').mockClear();
                state.processBeaconEvents([location, otherRelatedEvent], mockClient);
                expect(addLocationsSpy).not.toHaveBeenCalled();
@@ -945,13 +972,13 @@ describe("RoomState", function() {
                });
                jest.spyOn(decryptingRelatedEvent, 'isBeingDecrypted').mockReturnValue(true);
                state.setStateEvents([beacon1, beacon2]);
-                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1));
+                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1)) as Beacon;
                const addLocationsSpy = jest.spyOn(beacon, 'addLocations').mockClear();
                state.processBeaconEvents([decryptingRelatedEvent], mockClient);

                // this event is a message after decryption
-                decryptingRelatedEvent.type = EventType.RoomMessage;
-                decryptingRelatedEvent.emit(MatrixEventEvent.Decrypted);
+                decryptingRelatedEvent.event.type = EventType.RoomMessage;
+                decryptingRelatedEvent.emit(MatrixEventEvent.Decrypted, decryptingRelatedEvent);

                expect(addLocationsSpy).not.toHaveBeenCalled();
            });
@@ -967,14 +994,14 @@ describe("RoomState", function() {
                });
                jest.spyOn(decryptingRelatedEvent, 'isBeingDecrypted').mockReturnValue(true);
                state.setStateEvents([beacon1, beacon2]);
-                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1));
+                const beacon = state.beacons.get(getBeaconInfoIdentifier(beacon1)) as Beacon;
                const addLocationsSpy = jest.spyOn(beacon, 'addLocations').mockClear();
                state.processBeaconEvents([decryptingRelatedEvent], mockClient);

                // update type after '''decryption'''
                decryptingRelatedEvent.event.type = M_BEACON.name;
-                decryptingRelatedEvent.event.content = locationEvent.content;
-                decryptingRelatedEvent.emit(MatrixEventEvent.Decrypted);
+                decryptingRelatedEvent.event.content = locationEvent.event.content;
+                decryptingRelatedEvent.emit(MatrixEventEvent.Decrypted, decryptingRelatedEvent);

                expect(addLocationsSpy).toHaveBeenCalledWith([decryptingRelatedEvent]);
            });
@@ -361,6 +361,71 @@ describe("Room", function() {

            expect(callCount).toEqual(2);
        });
+
+        it("should be able to update local echo without a txn ID (/send then /sync)", function() {
+            const eventJson = utils.mkMessage({
+                room: roomId, user: userA, event: false,
+            }) as object;
+            delete eventJson["txn_id"];
+            delete eventJson["event_id"];
+            const localEvent = new MatrixEvent(Object.assign({ event_id: "$temp" }, eventJson));
+            localEvent.status = EventStatus.SENDING;
+            expect(localEvent.getTxnId()).toBeNull();
+            expect(room.timeline.length).toEqual(0);
+
+            // first add the local echo. This is done before the /send request is even sent.
+            const txnId = "My_txn_id";
+            room.addPendingEvent(localEvent, txnId);
+            expect(room.getEventForTxnId(txnId)).toEqual(localEvent);
+            expect(room.timeline.length).toEqual(1);
+
+            // now the /send request returns the true event ID.
+            const realEventId = "$real-event-id";
+            room.updatePendingEvent(localEvent, EventStatus.SENT, realEventId);
+
+            // then /sync returns the remoteEvent, it should de-dupe based on the event ID.
+            const remoteEvent = new MatrixEvent(Object.assign({ event_id: realEventId }, eventJson));
+            expect(remoteEvent.getTxnId()).toBeNull();
+            room.addLiveEvents([remoteEvent]);
+            // the duplicate strategy code should ensure we don't add a 2nd event to the live timeline
+            expect(room.timeline.length).toEqual(1);
+            // but without the event ID matching we will still have the local event in pending events
+            expect(room.getEventForTxnId(txnId)).toBeUndefined();
+        });
+
+        it("should be able to update local echo without a txn ID (/sync then /send)", function() {
+            const eventJson = utils.mkMessage({
+                room: roomId, user: userA, event: false,
+            }) as object;
+            delete eventJson["txn_id"];
+            delete eventJson["event_id"];
+            const txnId = "My_txn_id";
+            const localEvent = new MatrixEvent(Object.assign({ event_id: "$temp", txn_id: txnId }, eventJson));
+            localEvent.status = EventStatus.SENDING;
+            expect(localEvent.getTxnId()).toEqual(txnId);
+            expect(room.timeline.length).toEqual(0);
+
+            // first add the local echo. This is done before the /send request is even sent.
+            room.addPendingEvent(localEvent, txnId);
+            expect(room.getEventForTxnId(txnId)).toEqual(localEvent);
+            expect(room.timeline.length).toEqual(1);
+
+            // now the /sync returns the remoteEvent, it is impossible for the JS SDK to de-dupe this.
+            const realEventId = "$real-event-id";
+            const remoteEvent = new MatrixEvent(Object.assign({ event_id: realEventId }, eventJson));
+            expect(remoteEvent.getUnsigned().transaction_id).toBeUndefined();
+            room.addLiveEvents([remoteEvent]);
+            expect(room.timeline.length).toEqual(2); // impossible to de-dupe as no txn ID or matching event ID
+
+            // then the /send request returns the real event ID.
+            // Now it is possible for the JS SDK to de-dupe this.
+            room.updatePendingEvent(localEvent, EventStatus.SENT, realEventId);
+
+            // the 2nd event should be removed from the timeline.
+            expect(room.timeline.length).toEqual(1);
+            // but without the event ID matching we will still have the local event in pending events
+            expect(room.getEventForTxnId(txnId)).toBeUndefined();
+        });
    });

    describe('addEphemeralEvents', () => {
@@ -2370,16 +2435,126 @@ describe("Room", function() {
            expect(room.getEventReadUpTo(userA)).toEqual("eventId");
        });

-        it("prefers older receipt", () => {
-            room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
-                return (receiptType === ReceiptType.Read
-                    ? { eventId: "eventId1" }
-                    : { eventId: "eventId2" }
-                    ) as IWrappedReceipt;
-            };
-            room.getUnfilteredTimelineSet = () => ({ compareEventOrdering: (event1, event2) => 1 } as EventTimelineSet);
+        describe("prefers newer receipt", () => {
+            it("should compare correctly using timelines", () => {
+                room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                    if (receiptType === ReceiptType.ReadPrivate) {
+                        return { eventId: "eventId1" } as IWrappedReceipt;
+                    }
+                    if (receiptType === ReceiptType.UnstableReadPrivate) {
+                        return { eventId: "eventId2" } as IWrappedReceipt;
+                    }
+                    if (receiptType === ReceiptType.Read) {
+                        return { eventId: "eventId3" } as IWrappedReceipt;
+                    }
+                };

-            expect(room.getEventReadUpTo(userA)).toEqual("eventId1");
+                for (let i = 1; i <= 3; i++) {
+                    room.getUnfilteredTimelineSet = () => ({ compareEventOrdering: (event1, event2) => {
+                        return (event1 === `eventId${i}`) ? 1 : -1;
+                    } } as EventTimelineSet);
+
+                    expect(room.getEventReadUpTo(userA)).toEqual(`eventId${i}`);
+                }
+            });
+
+            describe("correctly compares by timestamp", () => {
+                it("should correctly compare, if we have all receipts", () => {
+                    for (let i = 1; i <= 3; i++) {
+                        room.getUnfilteredTimelineSet = () => ({
+                            compareEventOrdering: (_1, _2) => null,
+                        } as EventTimelineSet);
+                        room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                            if (receiptType === ReceiptType.ReadPrivate) {
+                                return { eventId: "eventId1", data: { ts: i === 1 ? 1 : 0 } } as IWrappedReceipt;
+                            }
+                            if (receiptType === ReceiptType.UnstableReadPrivate) {
+                                return { eventId: "eventId2", data: { ts: i === 2 ? 1 : 0 } } as IWrappedReceipt;
+                            }
+                            if (receiptType === ReceiptType.Read) {
+                                return { eventId: "eventId3", data: { ts: i === 3 ? 1 : 0 } } as IWrappedReceipt;
+                            }
+                        };
+
+                        expect(room.getEventReadUpTo(userA)).toEqual(`eventId${i}`);
+                    }
+                });
+
+                it("should correctly compare, if private read receipt is missing", () => {
+                    room.getUnfilteredTimelineSet = () => ({
+                        compareEventOrdering: (_1, _2) => null,
+                    } as EventTimelineSet);
+                    room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                        if (receiptType === ReceiptType.UnstableReadPrivate) {
+                            return { eventId: "eventId1", data: { ts: 0 } } as IWrappedReceipt;
+                        }
+                        if (receiptType === ReceiptType.Read) {
+                            return { eventId: "eventId2", data: { ts: 1 } } as IWrappedReceipt;
+                        }
+                    };
+
+                    expect(room.getEventReadUpTo(userA)).toEqual(`eventId2`);
+                });
+            });
+
+            describe("fallback precedence", () => {
+                beforeAll(() => {
+                    room.getUnfilteredTimelineSet = () => ({
+                        compareEventOrdering: (_1, _2) => null,
+                    } as EventTimelineSet);
+                });
+
+                it("should give precedence to m.read.private", () => {
+                    room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                        if (receiptType === ReceiptType.ReadPrivate) {
+                            return { eventId: "eventId1" } as IWrappedReceipt;
+                        }
+                        if (receiptType === ReceiptType.UnstableReadPrivate) {
+                            return { eventId: "eventId2" } as IWrappedReceipt;
+                        }
+                        if (receiptType === ReceiptType.Read) {
+                            return { eventId: "eventId3" } as IWrappedReceipt;
+                        }
+                    };
+
+                    expect(room.getEventReadUpTo(userA)).toEqual(`eventId1`);
+                });
+
+                it("should give precedence to org.matrix.msc2285.read.private", () => {
+                    room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                        if (receiptType === ReceiptType.UnstableReadPrivate) {
+                            return { eventId: "eventId2" } as IWrappedReceipt;
+                        }
+                        if (receiptType === ReceiptType.Read) {
+                            return { eventId: "eventId2" } as IWrappedReceipt;
+                        }
+                    };
+
+                    expect(room.getEventReadUpTo(userA)).toEqual(`eventId2`);
+                });
+
+                it("should give precedence to m.read", () => {
+                    room.getReadReceiptForUserId = (userId, ignore, receiptType) => {
+                        if (receiptType === ReceiptType.Read) {
+                            return { eventId: "eventId3" } as IWrappedReceipt;
+                        }
+                    };
+
+                    expect(room.getEventReadUpTo(userA)).toEqual(`eventId3`);
+                });
+            });
+        });
+    });
+
+    describe("roomNameGenerator", () => {
+        const client = new TestClient(userA).client;
+        client.roomNameGenerator = jest.fn().mockReturnValue(null);
+        const room = new Room(roomId, client, userA);
+
+        it("should call fn when recalculating room name", () => {
+            (client.roomNameGenerator as jest.Mock).mockClear();
+            room.recalculate();
+            expect(client.roomNameGenerator).toHaveBeenCalled();
        });
    });
 });
@@ -45,8 +45,8 @@ describe("MatrixScheduler", function() {
        queueFn = function() {
            return "one_big_queue";
        };
-        const deferA = defer();
-        const deferB = defer();
+        const deferA = defer<Record<string, boolean>>();
+        const deferB = defer<Record<string, boolean>>();
        let yieldedA = false;
        scheduler.setProcessFunction(function(event) {
            if (yieldedA) {
@@ -70,84 +70,84 @@ describe("MatrixScheduler", function() {
    });

    it("should invoke the retryFn on failure and wait the amount of time specified",
-    async function() {
-        const waitTimeMs = 1500;
-        const retryDefer = defer();
-        retryFn = function() {
-            retryDefer.resolve();
-            return waitTimeMs;
-        };
-        queueFn = function() {
-            return "yep";
-        };
+        async function() {
+            const waitTimeMs = 1500;
+            const retryDefer = defer();
+            retryFn = function() {
+                retryDefer.resolve();
+                return waitTimeMs;
+            };
+            queueFn = function() {
+                return "yep";
+            };

-        let procCount = 0;
-        scheduler.setProcessFunction(function(ev) {
-            procCount += 1;
-            if (procCount === 1) {
-                expect(ev).toEqual(eventA);
-                return deferred.promise;
-            } else if (procCount === 2) {
+            let procCount = 0;
+            scheduler.setProcessFunction(function(ev) {
+                procCount += 1;
+                if (procCount === 1) {
+                    expect(ev).toEqual(eventA);
+                    return deferred.promise;
+                } else if (procCount === 2) {
                // don't care about this deferred
-                return new Promise();
-            }
-            expect(procCount).toBeLessThan(3);
+                    return new Promise(() => {});
+                }
+                expect(procCount).toBeLessThan(3);
+            });
+
+            scheduler.queueEvent(eventA);
+            // as queueing doesn't start processing synchronously anymore (see commit bbdb5ac)
+            // wait just long enough before it does
+            await Promise.resolve();
+            expect(procCount).toEqual(1);
+            deferred.reject({});
+            await retryDefer.promise;
+            expect(procCount).toEqual(1);
+            jest.advanceTimersByTime(waitTimeMs);
+            await Promise.resolve();
+            expect(procCount).toEqual(2);
        });

-        scheduler.queueEvent(eventA);
-        // as queueing doesn't start processing synchronously anymore (see commit bbdb5ac)
-        // wait just long enough before it does
-        await Promise.resolve();
-        expect(procCount).toEqual(1);
-        deferred.reject({});
-        await retryDefer.promise;
-        expect(procCount).toEqual(1);
-        jest.advanceTimersByTime(waitTimeMs);
-        await Promise.resolve();
-        expect(procCount).toEqual(2);
-    });
-
    it("should give up if the retryFn on failure returns -1 and try the next event",
-    async function() {
+        async function() {
        // Queue A & B.
        // Reject A and return -1 on retry.
        // Expect B to be tried next and the promise for A to be rejected.
-        retryFn = function() {
-            return -1;
-        };
-        queueFn = function() {
-            return "yep";
-        };
+            retryFn = function() {
+                return -1;
+            };
+            queueFn = function() {
+                return "yep";
+            };

-        const deferA = defer();
-        const deferB = defer();
-        let procCount = 0;
-        scheduler.setProcessFunction(function(ev) {
-            procCount += 1;
-            if (procCount === 1) {
-                expect(ev).toEqual(eventA);
-                return deferA.promise;
-            } else if (procCount === 2) {
-                expect(ev).toEqual(eventB);
-                return deferB.promise;
-            }
-            expect(procCount).toBeLessThan(3);
-        });
+            const deferA = defer();
+            const deferB = defer();
+            let procCount = 0;
+            scheduler.setProcessFunction(function(ev) {
+                procCount += 1;
+                if (procCount === 1) {
+                    expect(ev).toEqual(eventA);
+                    return deferA.promise;
+                } else if (procCount === 2) {
+                    expect(ev).toEqual(eventB);
+                    return deferB.promise;
+                }
+                expect(procCount).toBeLessThan(3);
+            });

-        const globalA = scheduler.queueEvent(eventA);
-        scheduler.queueEvent(eventB);
-        // as queueing doesn't start processing synchronously anymore (see commit bbdb5ac)
-        // wait just long enough before it does
-        await Promise.resolve();
-        expect(procCount).toEqual(1);
-        deferA.reject({});
-        try {
-            await globalA;
-        } catch (err) {
+            const globalA = scheduler.queueEvent(eventA);
+            scheduler.queueEvent(eventB);
+            // as queueing doesn't start processing synchronously anymore (see commit bbdb5ac)
+            // wait just long enough before it does
            await Promise.resolve();
-            expect(procCount).toEqual(2);
-        }
-    });
+            expect(procCount).toEqual(1);
+            deferA.reject({});
+            try {
+                await globalA;
+            } catch (err) {
+                await Promise.resolve();
+                expect(procCount).toEqual(2);
+            }
+        });

    it("should treat each queue separately", function(done) {
        // Queue messages A B C D.
@@ -175,7 +175,7 @@ describe("MatrixScheduler", function() {
        const expectOrder = [
            eventA.getId(), eventB.getId(), eventD.getId(),
        ];
-        const deferA = defer();
+        const deferA = defer<void>();
        scheduler.setProcessFunction(function(event) {
            const id = expectOrder.shift();
            expect(id).toEqual(event.getId());
@@ -191,7 +191,7 @@ describe("MatrixScheduler", function() {

        // wait a bit then resolve A and we should get D (not C) next.
        setTimeout(function() {
-            deferA.resolve({});
+            deferA.resolve();
        }, 1000);
        jest.advanceTimersByTime(1000);
    });
@@ -336,28 +336,29 @@ describe("MatrixScheduler", function() {
                    errcode: "M_LIMIT_EXCEEDED", retry_after_ms: 5000,
                }),
            );
-            expect(res >= 500).toBe(true, "Didn't wait long enough.");
+            expect(res >= 500).toBe(true);
        });

        it("should give up after 5 attempts", function() {
            const res = MatrixScheduler.RETRY_BACKOFF_RATELIMIT(
-                eventA, 5, {},
+                eventA, 5, new MatrixError({}),
            );
-            expect(res).toBe(-1, "Didn't give up.");
+            expect(res).toBe(-1);
        });

        it("should do exponential backoff", function() {
+            const error = new MatrixError({});
            expect(MatrixScheduler.RETRY_BACKOFF_RATELIMIT(
-                eventA, 1, {},
+                eventA, 1, error,
            )).toEqual(2000);
            expect(MatrixScheduler.RETRY_BACKOFF_RATELIMIT(
-                eventA, 2, {},
+                eventA, 2, error,
            )).toEqual(4000);
            expect(MatrixScheduler.RETRY_BACKOFF_RATELIMIT(
-                eventA, 3, {},
+                eventA, 3, error,
            )).toEqual(8000);
            expect(MatrixScheduler.RETRY_BACKOFF_RATELIMIT(
-                eventA, 4, {},
+                eventA, 4, error,
            )).toEqual(16000);
        });
    });
@@ -1,6 +1,6 @@
 /*
 Copyright 2017 Vector Creations Ltd
-Copyright 2019 The Matrix.org Foundation C.I.C.
+Copyright 2019, 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -302,6 +302,9 @@ describe("SyncAccumulator", function() {
                    [ReceiptType.ReadPrivate]: {
                        "@dan:localhost": { ts: 4 },
                    },
+                    [ReceiptType.UnstableReadPrivate]: {
+                        "@matthew:localhost": { ts: 5 },
+                    },
                    "some.other.receipt.type": {
                        "@should_be_ignored:localhost": { key: "val" },
                    },
@@ -347,6 +350,9 @@ describe("SyncAccumulator", function() {
                    [ReceiptType.ReadPrivate]: {
                        "@dan:localhost": { ts: 4 },
                    },
+                    [ReceiptType.UnstableReadPrivate]: {
+                        "@matthew:localhost": { ts: 5 },
+                    },
                },
                "$event2:localhost": {
                    [ReceiptType.Read]: {
@@ -384,6 +390,10 @@ describe("SyncAccumulator", function() {
            };
        }

+        afterEach(() => {
+            jest.spyOn(global.Date, 'now').mockRestore();
+        });
+
        it("should copy summary properties", function() {
            sa.accumulate(createSyncResponseWithSummary({
                "m.heroes": ["@alice:bar"],
@@ -413,25 +423,19 @@ describe("SyncAccumulator", function() {
            const delta = 1000;
            const startingTs = 1000;

-            const oldDateNow = Date.now;
-            try {
-                Date.now = jest.fn();
-                Date.now.mockReturnValue(startingTs);
+            jest.spyOn(global.Date, 'now').mockReturnValue(startingTs);

-                sa.accumulate(RES_WITH_AGE);
+            sa.accumulate(RES_WITH_AGE);

-                Date.now.mockReturnValue(startingTs + delta);
+            jest.spyOn(global.Date, 'now').mockReturnValue(startingTs + delta);

-                const output = sa.getJSON();
-                expect(output.roomsData.join["!foo:bar"].timeline.events[0].unsigned.age).toEqual(
-                    RES_WITH_AGE.rooms.join["!foo:bar"].timeline.events[0].unsigned.age + delta,
-                );
-                expect(Object.keys(output.roomsData.join["!foo:bar"].timeline.events[0])).toEqual(
-                    Object.keys(RES_WITH_AGE.rooms.join["!foo:bar"].timeline.events[0]),
-                );
-            } finally {
-                Date.now = oldDateNow;
-            }
+            const output = sa.getJSON();
+            expect(output.roomsData.join["!foo:bar"].timeline.events[0].unsigned.age).toEqual(
+                RES_WITH_AGE.rooms.join["!foo:bar"].timeline.events[0].unsigned.age + delta,
+            );
+            expect(Object.keys(output.roomsData.join["!foo:bar"].timeline.events[0])).toEqual(
+                Object.keys(RES_WITH_AGE.rooms.join["!foo:bar"].timeline.events[0]),
+            );
        });

        it("should mangle age without adding extra keys", () => {
@@ -1,456 +0,0 @@
-import { EventTimeline } from "../../src/models/event-timeline";
-import { TimelineIndex, TimelineWindow } from "../../src/timeline-window";
-import * as utils from "../test-utils/test-utils";
-
-const ROOM_ID = "roomId";
-const USER_ID = "userId";
-
-/*
- * create a timeline with a bunch (default 3) events.
- * baseIndex is 1 by default.
- */
-function createTimeline(numEvents, baseIndex) {
-    if (numEvents === undefined) {
-        numEvents = 3;
-    }
-    if (baseIndex === undefined) {
-        baseIndex = 1;
-    }
-
-    // XXX: this is a horrid hack
-    const timelineSet = { room: { roomId: ROOM_ID } };
-    timelineSet.room.getUnfilteredTimelineSet = function() {
-        return timelineSet;
-    };
-
-    const timeline = new EventTimeline(timelineSet);
-
-    // add the events after the baseIndex first
-    addEventsToTimeline(timeline, numEvents - baseIndex, false);
-
-    // then add those before the baseIndex
-    addEventsToTimeline(timeline, baseIndex, true);
-
-    expect(timeline.getBaseIndex()).toEqual(baseIndex);
-    return timeline;
-}
-
-function addEventsToTimeline(timeline, numEvents, toStartOfTimeline) {
-    for (let i = 0; i < numEvents; i++) {
-        timeline.addEvent(
-            utils.mkMessage({
-                room: ROOM_ID, user: USER_ID,
-                event: true,
-            }),
-            { toStartOfTimeline },
-        );
-    }
-}
-
-/*
- * create a pair of linked timelines
- */
-function createLinkedTimelines() {
-    const tl1 = createTimeline();
-    const tl2 = createTimeline();
-    tl1.setNeighbouringTimeline(tl2, EventTimeline.FORWARDS);
-    tl2.setNeighbouringTimeline(tl1, EventTimeline.BACKWARDS);
-    return [tl1, tl2];
-}
-
-describe("TimelineIndex", function() {
-    describe("minIndex", function() {
-        it("should return the min index relative to BaseIndex", function() {
-            const timelineIndex = new TimelineIndex(createTimeline(), 0);
-            expect(timelineIndex.minIndex()).toEqual(-1);
-        });
-    });
-
-    describe("maxIndex", function() {
-        it("should return the max index relative to BaseIndex", function() {
-            const timelineIndex = new TimelineIndex(createTimeline(), 0);
-            expect(timelineIndex.maxIndex()).toEqual(2);
-        });
-    });
-
-    describe("advance", function() {
-        it("should advance up to the end of the timeline", function() {
-            const timelineIndex = new TimelineIndex(createTimeline(), 0);
-            const result = timelineIndex.advance(3);
-            expect(result).toEqual(2);
-            expect(timelineIndex.index).toEqual(2);
-        });
-
-        it("should retreat back to the start of the timeline", function() {
-            const timelineIndex = new TimelineIndex(createTimeline(), 0);
-            const result = timelineIndex.advance(-2);
-            expect(result).toEqual(-1);
-            expect(timelineIndex.index).toEqual(-1);
-        });
-
-        it("should advance into the next timeline", function() {
-            const timelines = createLinkedTimelines();
-            const tl1 = timelines[0];
-            const tl2 = timelines[1];
-
-            // initialise the index pointing at the end of the first timeline
-            const timelineIndex = new TimelineIndex(tl1, 2);
-
-            const result = timelineIndex.advance(1);
-            expect(result).toEqual(1);
-            expect(timelineIndex.timeline).toBe(tl2);
-
-            // we expect the index to be the zero (ie, the same as the
-            // BaseIndex), because the BaseIndex points at the second event,
-            // and we've advanced past the first.
-            expect(timelineIndex.index).toEqual(0);
-        });
-
-        it("should retreat into the previous timeline", function() {
-            const timelines = createLinkedTimelines();
-            const tl1 = timelines[0];
-            const tl2 = timelines[1];
-
-            // initialise the index pointing at the start of the second
-            // timeline
-            const timelineIndex = new TimelineIndex(tl2, -1);
-
-            const result = timelineIndex.advance(-1);
-            expect(result).toEqual(-1);
-            expect(timelineIndex.timeline).toBe(tl1);
-            expect(timelineIndex.index).toEqual(1);
-        });
-    });
-
-    describe("retreat", function() {
-        it("should retreat up to the start of the timeline", function() {
-            const timelineIndex = new TimelineIndex(createTimeline(), 0);
-            const result = timelineIndex.retreat(2);
-            expect(result).toEqual(1);
-            expect(timelineIndex.index).toEqual(-1);
-        });
-    });
-});
-
-describe("TimelineWindow", function() {
-    /**
-     * create a dummy eventTimelineSet and client, and a TimelineWindow
-     * attached to them.
-     */
-    let timelineSet;
-    let client;
-    function createWindow(timeline, opts) {
-        timelineSet = { getTimelineForEvent: () => null };
-        client = {};
-        client.getEventTimeline = function(timelineSet0, eventId0) {
-            expect(timelineSet0).toBe(timelineSet);
-            return Promise.resolve(timeline);
-        };
-
-        return new TimelineWindow(client, timelineSet, opts);
-    }
-
-    describe("load", function() {
-        it("should initialise from the live timeline", function() {
-            const liveTimeline = createTimeline();
-            const room = {};
-            room.getLiveTimeline = function() {
-                return liveTimeline;
-            };
-
-            const timelineWindow = new TimelineWindow(undefined, room);
-            return timelineWindow.load(undefined, 2).then(function() {
-                const expectedEvents = liveTimeline.getEvents().slice(1);
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-            });
-        });
-
-        it("should initialise from a specific event", function() {
-            const timeline = createTimeline();
-            const eventId = timeline.getEvents()[1].getId();
-
-            const timelineSet = { getTimelineForEvent: () => null };
-            const client = {};
-            client.getEventTimeline = function(timelineSet0, eventId0) {
-                expect(timelineSet0).toBe(timelineSet);
-                expect(eventId0).toEqual(eventId);
-                return Promise.resolve(timeline);
-            };
-
-            const timelineWindow = new TimelineWindow(client, timelineSet);
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-            });
-        });
-
-        it("canPaginate should return false until load has returned", function() {
-            const timeline = createTimeline();
-            timeline.setPaginationToken("toktok1", EventTimeline.BACKWARDS);
-            timeline.setPaginationToken("toktok2", EventTimeline.FORWARDS);
-
-            const eventId = timeline.getEvents()[1].getId();
-
-            const timelineSet = { getTimelineForEvent: () => null };
-            const client = {};
-
-            const timelineWindow = new TimelineWindow(client, timelineSet);
-
-            client.getEventTimeline = function(timelineSet0, eventId0) {
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-                return Promise.resolve(timeline);
-            };
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-            });
-        });
-    });
-
-    describe("pagination", function() {
-        it("should be able to advance across the initial timeline", function() {
-            const timeline = createTimeline();
-            const eventId = timeline.getEvents()[1].getId();
-            const timelineWindow = createWindow(timeline);
-
-            return timelineWindow.load(eventId, 1).then(function() {
-                const expectedEvents = [timeline.getEvents()[1]];
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = timeline.getEvents().slice(1);
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(false);
-
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(false);
-            });
-        });
-
-        it("should advance into next timeline", function() {
-            const tls = createLinkedTimelines();
-            const eventId = tls[0].getEvents()[1].getId();
-            const timelineWindow = createWindow(tls[0], { windowLimit: 5 });
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = tls[0].getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = tls[0].getEvents()
-                    .concat(tls[1].getEvents().slice(0, 2));
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                // the windowLimit should have made us drop an event from
-                // tls[0]
-                const expectedEvents = tls[0].getEvents().slice(1)
-                    .concat(tls[1].getEvents());
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(false);
-            });
-        });
-
-        it("should retreat into previous timeline", function() {
-            const tls = createLinkedTimelines();
-            const eventId = tls[1].getEvents()[1].getId();
-            const timelineWindow = createWindow(tls[1], { windowLimit: 5 });
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = tls[1].getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = tls[0].getEvents().slice(1, 3)
-                    .concat(tls[1].getEvents());
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                // the windowLimit should have made us drop an event from
-                // tls[1]
-                const expectedEvents = tls[0].getEvents()
-                    .concat(tls[1].getEvents().slice(0, 2));
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(false);
-            });
-        });
-
-        it("should make forward pagination requests", function() {
-            const timeline = createTimeline();
-            timeline.setPaginationToken("toktok", EventTimeline.FORWARDS);
-
-            const timelineWindow = createWindow(timeline, { windowLimit: 5 });
-            const eventId = timeline.getEvents()[1].getId();
-
-            client.paginateEventTimeline = function(timeline0, opts) {
-                expect(timeline0).toBe(timeline);
-                expect(opts.backwards).toBe(false);
-                expect(opts.limit).toEqual(2);
-
-                addEventsToTimeline(timeline, 3, false);
-                return Promise.resolve(true);
-            };
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = timeline.getEvents().slice(0, 5);
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-            });
-        });
-
-        it("should make backward pagination requests", function() {
-            const timeline = createTimeline();
-            timeline.setPaginationToken("toktok", EventTimeline.BACKWARDS);
-
-            const timelineWindow = createWindow(timeline, { windowLimit: 5 });
-            const eventId = timeline.getEvents()[1].getId();
-
-            client.paginateEventTimeline = function(timeline0, opts) {
-                expect(timeline0).toBe(timeline);
-                expect(opts.backwards).toBe(true);
-                expect(opts.limit).toEqual(2);
-
-                addEventsToTimeline(timeline, 3, true);
-                return Promise.resolve(true);
-            };
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(true);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(false);
-                return timelineWindow.paginate(EventTimeline.BACKWARDS, 2);
-            }).then(function(success) {
-                expect(success).toBe(true);
-                const expectedEvents = timeline.getEvents().slice(1, 6);
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-            });
-        });
-
-        it("should limit the number of unsuccessful pagination requests", function() {
-            const timeline = createTimeline();
-            timeline.setPaginationToken("toktok", EventTimeline.FORWARDS);
-
-            const timelineWindow = createWindow(timeline, { windowLimit: 5 });
-            const eventId = timeline.getEvents()[1].getId();
-
-            let paginateCount = 0;
-            client.paginateEventTimeline = function(timeline0, opts) {
-                expect(timeline0).toBe(timeline);
-                expect(opts.backwards).toBe(false);
-                expect(opts.limit).toEqual(2);
-                paginateCount += 1;
-                return Promise.resolve(true);
-            };
-
-            return timelineWindow.load(eventId, 3).then(function() {
-                const expectedEvents = timeline.getEvents();
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-                return timelineWindow.paginate(EventTimeline.FORWARDS, 2, true, 3);
-            }).then(function(success) {
-                expect(success).toBe(false);
-                expect(paginateCount).toEqual(3);
-                const expectedEvents = timeline.getEvents().slice(0, 3);
-                expect(timelineWindow.getEvents()).toEqual(expectedEvents);
-
-                expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
-                    .toBe(false);
-                expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
-                    .toBe(true);
-            });
-        });
-    });
-});
@@ -0,0 +1,439 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { MockedObject } from 'jest-mock';
+
+import { MatrixClient } from "../../src/client";
+import { EventTimelineSet } from "../../src/models/event-timeline-set";
+import { Room } from "../../src/models/room";
+import { EventTimeline } from "../../src/models/event-timeline";
+import { TimelineIndex, TimelineWindow } from "../../src/timeline-window";
+import { mkMessage } from "../test-utils/test-utils";
+
+const ROOM_ID = "roomId";
+const USER_ID = "userId";
+const mockClient = {
+    getEventTimeline: jest.fn(),
+    paginateEventTimeline: jest.fn(),
+} as unknown as MockedObject<MatrixClient>;
+
+/*
+ * create a timeline with a bunch (default 3) events.
+ * baseIndex is 1 by default.
+ */
+function createTimeline(numEvents = 3, baseIndex = 1): EventTimeline {
+    const room = new Room(ROOM_ID, mockClient, USER_ID);
+    const timelineSet = new EventTimelineSet(room);
+    jest.spyOn(timelineSet.room, 'getUnfilteredTimelineSet').mockReturnValue(timelineSet);
+
+    const timeline = new EventTimeline(timelineSet);
+
+    // add the events after the baseIndex first
+    addEventsToTimeline(timeline, numEvents - baseIndex, false);
+
+    // then add those before the baseIndex
+    addEventsToTimeline(timeline, baseIndex, true);
+
+    expect(timeline.getBaseIndex()).toEqual(baseIndex);
+    return timeline;
+}
+
+function addEventsToTimeline(timeline: EventTimeline, numEvents: number, toStartOfTimeline: boolean) {
+    for (let i = 0; i < numEvents; i++) {
+        timeline.addEvent(
+            mkMessage({
+                room: ROOM_ID, user: USER_ID,
+                event: true,
+            }),
+            { toStartOfTimeline },
+        );
+    }
+}
+
+/*
+ * create a pair of linked timelines
+ */
+function createLinkedTimelines(): [EventTimeline, EventTimeline] {
+    const tl1 = createTimeline();
+    const tl2 = createTimeline();
+    tl1.setNeighbouringTimeline(tl2, EventTimeline.FORWARDS);
+    tl2.setNeighbouringTimeline(tl1, EventTimeline.BACKWARDS);
+    return [tl1, tl2];
+}
+
+describe("TimelineIndex", function() {
+    beforeEach(() => {
+        jest.clearAllMocks();
+        mockClient.getEventTimeline.mockResolvedValue(undefined);
+    });
+
+    describe("minIndex", function() {
+        it("should return the min index relative to BaseIndex", function() {
+            const timelineIndex = new TimelineIndex(createTimeline(), 0);
+            expect(timelineIndex.minIndex()).toEqual(-1);
+        });
+    });
+
+    describe("maxIndex", function() {
+        it("should return the max index relative to BaseIndex", function() {
+            const timelineIndex = new TimelineIndex(createTimeline(), 0);
+            expect(timelineIndex.maxIndex()).toEqual(2);
+        });
+    });
+
+    describe("advance", function() {
+        it("should advance up to the end of the timeline", function() {
+            const timelineIndex = new TimelineIndex(createTimeline(), 0);
+            const result = timelineIndex.advance(3);
+            expect(result).toEqual(2);
+            expect(timelineIndex.index).toEqual(2);
+        });
+
+        it("should retreat back to the start of the timeline", function() {
+            const timelineIndex = new TimelineIndex(createTimeline(), 0);
+            const result = timelineIndex.advance(-2);
+            expect(result).toEqual(-1);
+            expect(timelineIndex.index).toEqual(-1);
+        });
+
+        it("should advance into the next timeline", function() {
+            const timelines = createLinkedTimelines();
+            const tl1 = timelines[0];
+            const tl2 = timelines[1];
+
+            // initialise the index pointing at the end of the first timeline
+            const timelineIndex = new TimelineIndex(tl1, 2);
+
+            const result = timelineIndex.advance(1);
+            expect(result).toEqual(1);
+            expect(timelineIndex.timeline).toBe(tl2);
+
+            // we expect the index to be the zero (ie, the same as the
+            // BaseIndex), because the BaseIndex points at the second event,
+            // and we've advanced past the first.
+            expect(timelineIndex.index).toEqual(0);
+        });
+
+        it("should retreat into the previous timeline", function() {
+            const timelines = createLinkedTimelines();
+            const tl1 = timelines[0];
+            const tl2 = timelines[1];
+
+            // initialise the index pointing at the start of the second
+            // timeline
+            const timelineIndex = new TimelineIndex(tl2, -1);
+
+            const result = timelineIndex.advance(-1);
+            expect(result).toEqual(-1);
+            expect(timelineIndex.timeline).toBe(tl1);
+            expect(timelineIndex.index).toEqual(1);
+        });
+    });
+
+    describe("retreat", function() {
+        it("should retreat up to the start of the timeline", function() {
+            const timelineIndex = new TimelineIndex(createTimeline(), 0);
+            const result = timelineIndex.retreat(2);
+            expect(result).toEqual(1);
+            expect(timelineIndex.index).toEqual(-1);
+        });
+    });
+});
+
+describe("TimelineWindow", function() {
+    /**
+     * create a dummy eventTimelineSet and client, and a TimelineWindow
+     * attached to them.
+     */
+    function createWindow(timeline: EventTimeline, opts?: {
+        windowLimit?: number;
+    }): [TimelineWindow, EventTimelineSet] {
+        const timelineSet = { getTimelineForEvent: () => null } as unknown as EventTimelineSet;
+        mockClient.getEventTimeline.mockResolvedValue(timeline);
+
+        return [new TimelineWindow(mockClient, timelineSet, opts), timelineSet];
+    }
+
+    beforeEach(() => {
+        jest.clearAllMocks();
+        mockClient.getEventTimeline.mockResolvedValue(undefined);
+        mockClient.paginateEventTimeline.mockReturnValue(undefined);
+    });
+
+    describe("load", function() {
+        it("should initialise from the live timeline", async function() {
+            const liveTimeline = createTimeline();
+            const room = new Room(ROOM_ID, mockClient, USER_ID);
+            const timelineSet = new EventTimelineSet(room);
+            jest.spyOn(timelineSet, 'getLiveTimeline').mockReturnValue(liveTimeline);
+
+            const timelineWindow = new TimelineWindow(mockClient, timelineSet);
+            await timelineWindow.load(undefined, 2);
+
+            expect(timelineSet.getLiveTimeline).toHaveBeenCalled();
+
+            const expectedEvents = liveTimeline.getEvents().slice(1);
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+        });
+
+        it("should initialise from a specific event", async function() {
+            const timeline = createTimeline();
+            const eventId = timeline.getEvents()[1].getId();
+
+            const timelineSet = { getTimelineForEvent: () => null } as unknown as EventTimelineSet;
+            mockClient.getEventTimeline.mockResolvedValue(timeline);
+
+            const timelineWindow = new TimelineWindow(mockClient, timelineSet);
+            await timelineWindow.load(eventId, 3);
+            expect(mockClient.getEventTimeline).toHaveBeenCalledWith(timelineSet, eventId);
+            const expectedEvents = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+        });
+
+        it("canPaginate should return false until load has returned", async function() {
+            const timeline = createTimeline();
+            timeline.setPaginationToken("toktok1", EventTimeline.BACKWARDS);
+            timeline.setPaginationToken("toktok2", EventTimeline.FORWARDS);
+
+            const eventId = timeline.getEvents()[1].getId();
+
+            const timelineSet = { getTimelineForEvent: () => null } as unknown as EventTimelineSet;
+            mockClient.getEventTimeline.mockResolvedValue(timeline);
+
+            const timelineWindow = new TimelineWindow(mockClient, timelineSet);
+
+            const timelineWindowLoadPromise = timelineWindow.load(eventId, 3);
+
+            // cannot paginate before load is complete
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS)).toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS)).toBe(false);
+
+            // wait for load
+            await timelineWindowLoadPromise;
+            const expectedEvents = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            // can paginate now
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+        });
+    });
+
+    describe("pagination", function() {
+        it("should be able to advance across the initial timeline", async function() {
+            const timeline = createTimeline();
+            const eventId = timeline.getEvents()[1].getId();
+            const [timelineWindow] = createWindow(timeline);
+
+            await timelineWindow.load(eventId, 1);
+
+            const expectedEvents = [timeline.getEvents()[1]];
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(true);
+            const expectedEventsAfterPagination = timeline.getEvents().slice(1);
+            expect(timelineWindow.getEvents()).toEqual(expectedEventsAfterPagination);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(false);
+
+            // cant paginate forward anymore
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(false);
+
+            // paginate back again
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(true);
+
+            const expectedEvents3 = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents3);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(false);
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(false);
+        });
+
+        it("should advance into next timeline", async function() {
+            const tls = createLinkedTimelines();
+            const eventId = tls[0].getEvents()[1].getId();
+            const [timelineWindow] = createWindow(tls[0], { windowLimit: 5 });
+
+            await timelineWindow.load(eventId, 3);
+            const expectedEvents = tls[0].getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(true);
+            const expectedEvents2 = tls[0].getEvents()
+                .concat(tls[1].getEvents().slice(0, 2));
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents2);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(true);
+
+            // the windowLimit should have made us drop an event from
+            // tls[0]
+            const expectedEvents3 = tls[0].getEvents().slice(1)
+                .concat(tls[1].getEvents());
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents3);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(false);
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(false);
+        });
+
+        it("should retreat into previous timeline", async function() {
+            const tls = createLinkedTimelines();
+            const eventId = tls[1].getEvents()[1].getId();
+            const [timelineWindow] = createWindow(tls[1], { windowLimit: 5 });
+
+            await timelineWindow.load(eventId, 3);
+
+            const expectedEvents = tls[1].getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(false);
+
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(true);
+            const expectedEvents2 = tls[0].getEvents().slice(1, 3)
+                .concat(tls[1].getEvents());
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents2);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(false);
+
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(true);
+            // the windowLimit should have made us drop an event from
+            // tls[1]
+            const expectedEvents3 = tls[0].getEvents()
+                .concat(tls[1].getEvents().slice(0, 2));
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents3);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(false);
+        });
+
+        it("should make forward pagination requests", async function() {
+            const timeline = createTimeline();
+            timeline.setPaginationToken("toktok", EventTimeline.FORWARDS);
+
+            const [timelineWindow] = createWindow(timeline, { windowLimit: 5 });
+            const eventId = timeline.getEvents()[1].getId();
+
+            mockClient.paginateEventTimeline.mockImplementation(async (_t, _opts) => {
+                addEventsToTimeline(timeline, 3, false);
+                return true;
+            });
+
+            await timelineWindow.load(eventId, 3);
+            const expectedEvents = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS)).toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS)).toBe(true);
+
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2)).toBe(true);
+            expect(mockClient.paginateEventTimeline).toHaveBeenCalledWith(timeline, { backwards: false, limit: 2 });
+            const expectedEvents2 = timeline.getEvents().slice(0, 5);
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents2);
+        });
+
+        it("should make backward pagination requests", async function() {
+            const timeline = createTimeline();
+            timeline.setPaginationToken("toktok", EventTimeline.BACKWARDS);
+
+            const [timelineWindow] = createWindow(timeline, { windowLimit: 5 });
+            const eventId = timeline.getEvents()[1].getId();
+
+            mockClient.paginateEventTimeline.mockImplementation(async (_t, _opts) => {
+                addEventsToTimeline(timeline, 3, true);
+                return true;
+            });
+
+            await timelineWindow.load(eventId, 3);
+            const expectedEvents = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS)).toBe(true);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS)).toBe(false);
+
+            expect(await timelineWindow.paginate(EventTimeline.BACKWARDS, 2)).toBe(true);
+            expect(mockClient.paginateEventTimeline).toHaveBeenCalledWith(timeline, { backwards: true, limit: 2 });
+
+            const expectedEvents2 = timeline.getEvents().slice(1, 6);
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents2);
+        });
+
+        it("should limit the number of unsuccessful pagination requests", async function() {
+            const timeline = createTimeline();
+            timeline.setPaginationToken("toktok", EventTimeline.FORWARDS);
+
+            const [timelineWindow] = createWindow(timeline, { windowLimit: 5 });
+            const eventId = timeline.getEvents()[1].getId();
+
+            mockClient.paginateEventTimeline.mockImplementation(async (_t, _opts) => {
+                return true;
+            });
+
+            await timelineWindow.load(eventId, 3);
+            const expectedEvents = timeline.getEvents();
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+            expect(await timelineWindow.paginate(EventTimeline.FORWARDS, 2, true, 3)).toBe(false);
+
+            expect(mockClient.paginateEventTimeline).toHaveBeenCalledWith(timeline, { backwards: false, limit: 2 });
+
+            expect(mockClient.paginateEventTimeline).toHaveBeenCalledTimes(3);
+            const expectedEvents2 = timeline.getEvents().slice(0, 3);
+            expect(timelineWindow.getEvents()).toEqual(expectedEvents2);
+
+            expect(timelineWindow.canPaginate(EventTimeline.BACKWARDS))
+                .toBe(false);
+            expect(timelineWindow.canPaginate(EventTimeline.FORWARDS))
+                .toBe(true);
+        });
+    });
+});
@@ -1,16 +1,32 @@
-import { User } from "../../src/models/user";
-import * as utils from "../test-utils/test-utils";
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { User, UserEvent } from "../../src/models/user";
+import { mkEvent } from "../test-utils/test-utils";

 describe("User", function() {
    const userId = "@alice:bar";
-    let user;
+    let user: User;

    beforeEach(function() {
        user = new User(userId);
    });

    describe("setPresenceEvent", function() {
-        const event = utils.mkEvent({
+        const event = mkEvent({
            type: "m.presence", content: {
                presence: "online",
                user_id: userId,
@@ -22,7 +38,7 @@ describe("User", function() {

        it("should emit 'User.displayName' if the display name changes", function() {
            let emitCount = 0;
-            user.on("User.displayName", function(ev, usr) {
+            user.on(UserEvent.DisplayName, function(ev, usr) {
                emitCount += 1;
            });
            user.setPresenceEvent(event);
@@ -33,7 +49,7 @@ describe("User", function() {

        it("should emit 'User.avatarUrl' if the avatar URL changes", function() {
            let emitCount = 0;
-            user.on("User.avatarUrl", function(ev, usr) {
+            user.on(UserEvent.AvatarUrl, function(ev, usr) {
                emitCount += 1;
            });
            user.setPresenceEvent(event);
@@ -44,7 +60,7 @@ describe("User", function() {

        it("should emit 'User.presence' if the presence changes", function() {
            let emitCount = 0;
-            user.on("User.presence", function(ev, usr) {
+            user.on(UserEvent.Presence, function(ev, usr) {
                emitCount += 1;
            });
            user.setPresenceEvent(event);
@@ -15,6 +15,7 @@ import {
 import { logger } from "../../src/logger";
 import { mkMessage } from "../test-utils/test-utils";
 import { makeBeaconEvent } from "../test-utils/beacon";
+import { ReceiptType } from "../../src/@types/read_receipts";

 // TODO: Fix types throughout

@@ -151,6 +152,9 @@ describe("utils", function() {
            assert.isTrue(utils.deepCompare({ a: 1, b: 2 }, { a: 1, b: 2 }));
            assert.isTrue(utils.deepCompare({ a: 1, b: 2 }, { b: 2, a: 1 }));
            assert.isFalse(utils.deepCompare({ a: 1, b: 2 }, { a: 1, b: 3 }));
+            assert.isFalse(utils.deepCompare({ a: 1, b: 2 }, { a: 1 }));
+            assert.isFalse(utils.deepCompare({ a: 1 }, { a: 1, b: 2 }));
+            assert.isFalse(utils.deepCompare({ a: 1 }, { b: 1 }));

            assert.isTrue(utils.deepCompare({
                1: { name: "mhc", age: 28 },
@@ -523,4 +527,54 @@ describe("utils", function() {
            ).toEqual([beaconEvent2, beaconEvent1, beaconEvent3]);
        });
    });
+
+    describe('getPrivateReadReceiptField', () => {
+        it('should return m.read.private if server supports stable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return feature === "org.matrix.msc2285.stable";
+                }),
+            } as any)).toBe(ReceiptType.ReadPrivate);
+        });
+
+        it('should return m.read.private if server supports stable and unstable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return ["org.matrix.msc2285.stable", "org.matrix.msc2285"].includes(feature);
+                }),
+            } as any)).toBe(ReceiptType.ReadPrivate);
+        });
+
+        it('should return org.matrix.msc2285.read.private if server supports  unstable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return feature === "org.matrix.msc2285";
+                }),
+            } as any)).toBe(ReceiptType.UnstableReadPrivate);
+        });
+
+        it('should return none if server does not support either', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockResolvedValue(false),
+            } as any)).toBeFalsy();
+        });
+    });
+
+    describe('isSupportedReceiptType', () => {
+        it('should support m.read', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.Read)).toBeTruthy();
+        });
+
+        it('should support m.read.private', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.ReadPrivate)).toBeTruthy();
+        });
+
+        it('should support org.matrix.msc2285.read.private', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.UnstableReadPrivate)).toBeTruthy();
+        });
+
+        it('should not support other receipt types', () => {
+            expect(utils.isSupportedReceiptType("this is a receipt type")).toBeFalsy();
+        });
+    });
 });
@@ -391,71 +391,6 @@ describe('Call', function() {
        }).track.id).toBe("video_track");
    });

-    describe("should handle stream replacement", () => {
-        it("with both purpose and id", async () => {
-            await startVoiceCall(client, call);
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream1": {
-                    purpose: SDPStreamMetadataPurpose.Usermedia,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream1", []));
-            const feed = call.getFeeds().find((feed) => feed.stream.id === "remote_stream1");
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream2": {
-                    purpose: SDPStreamMetadataPurpose.Usermedia,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream2", []));
-
-            expect(feed?.stream?.id).toBe("remote_stream2");
-        });
-
-        it("with just purpose", async () => {
-            await startVoiceCall(client, call);
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream1": {
-                    purpose: SDPStreamMetadataPurpose.Usermedia,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream1", []));
-            const feed = call.getFeeds().find((feed) => feed.stream.id === "remote_stream1");
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream2": {
-                    purpose: SDPStreamMetadataPurpose.Usermedia,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream2", []));
-
-            expect(feed?.stream?.id).toBe("remote_stream2");
-        });
-
-        it("should not replace purpose is different", async () => {
-            await startVoiceCall(client, call);
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream1": {
-                    purpose: SDPStreamMetadataPurpose.Usermedia,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream1", []));
-            const feed = call.getFeeds().find((feed) => feed.stream.id === "remote_stream1");
-
-            call.updateRemoteSDPStreamMetadata({
-                "remote_stream2": {
-                    purpose: SDPStreamMetadataPurpose.Screenshare,
-                },
-            });
-            call.pushRemoteFeed(new MockMediaStream("remote_stream2", []));
-
-            expect(feed?.stream?.id).toBe("remote_stream1");
-        });
-    });
-
    it("should handle SDPStreamMetadata changes", async () => {
        await startVoiceCall(client, call);

@@ -758,4 +693,63 @@ describe('Call', function() {
            expect(supportsMatrixCall()).toBe(false);
        });
    });
+
+    describe("ignoring streams with ids for which we already have a feed", () => {
+        const STREAM_ID = "stream_id";
+        const FEEDS_CHANGED_CALLBACK = jest.fn();
+
+        beforeEach(async () => {
+            await startVoiceCall(client, call);
+            call.on(CallEvent.FeedsChanged, FEEDS_CHANGED_CALLBACK);
+            jest.spyOn(call, "pushLocalFeed");
+        });
+
+        afterEach(() => {
+            FEEDS_CHANGED_CALLBACK.mockReset();
+        });
+
+        it("should ignore stream passed to pushRemoteFeed()", async () => {
+            await call.onAnswerReceived({
+                getContent: () => {
+                    return {
+                        version: 1,
+                        call_id: call.callId,
+                        party_id: 'party_id',
+                        answer: {
+                            sdp: DUMMY_SDP,
+                        },
+                        [SDPStreamMetadataKey]: {
+                            [STREAM_ID]: {
+                                purpose: SDPStreamMetadataPurpose.Usermedia,
+                            },
+                        },
+                    };
+                },
+            });
+
+            call.pushRemoteFeed(new MockMediaStream(STREAM_ID));
+            call.pushRemoteFeed(new MockMediaStream(STREAM_ID));
+
+            expect(call.getRemoteFeeds().length).toBe(1);
+            expect(FEEDS_CHANGED_CALLBACK).toHaveBeenCalledTimes(1);
+        });
+
+        it("should ignore stream passed to pushRemoteFeedWithoutMetadata()", async () => {
+            call.pushRemoteFeedWithoutMetadata(new MockMediaStream(STREAM_ID));
+            call.pushRemoteFeedWithoutMetadata(new MockMediaStream(STREAM_ID));
+
+            expect(call.getRemoteFeeds().length).toBe(1);
+            expect(FEEDS_CHANGED_CALLBACK).toHaveBeenCalledTimes(1);
+        });
+
+        it("should ignore stream passed to pushNewLocalFeed()", async () => {
+            call.pushNewLocalFeed(new MockMediaStream(STREAM_ID), SDPStreamMetadataPurpose.Screenshare);
+            call.pushNewLocalFeed(new MockMediaStream(STREAM_ID), SDPStreamMetadataPurpose.Screenshare);
+
+            // We already have one local feed from placeVoiceCall()
+            expect(call.getLocalFeeds().length).toBe(2);
+            expect(FEEDS_CHANGED_CALLBACK).toHaveBeenCalledTimes(1);
+            expect(call.pushLocalFeed).toHaveBeenCalled();
+        });
+    });
 });
@@ -15,13 +15,11 @@ limitations under the License.
 */

 import { SDPStreamMetadataPurpose } from "../../../src/webrtc/callEventTypes";
-import { CallFeed, CallFeedEvent } from "../../../src/webrtc/callFeed";
-import { MockMediaStream, MockMediaStreamTrack } from "../../test-utils/webrtc";
+import { CallFeed } from "../../../src/webrtc/callFeed";
 import { TestClient } from "../../TestClient";
+import { MockMediaStream, MockMediaStreamTrack } from "../../test-utils/webrtc";

 describe("CallFeed", () => {
-    const roomId = "room_id";
-
    let client;

    beforeEach(() => {
@@ -32,30 +30,60 @@ describe("CallFeed", () => {
        client.stop();
    });

-    it("should handle stream replacement", () => {
-        const feedNewStreamCallback = jest.fn();
-        const feed = new CallFeed({
-            client,
-            roomId,
-            userId: "user1",
-            // @ts-ignore Mock
-            stream: new MockMediaStream("stream1"),
-            id: "id",
-            purpose: SDPStreamMetadataPurpose.Usermedia,
-            audioMuted: false,
-            videoMuted: false,
+    describe("muting", () => {
+        let feed: CallFeed;
+
+        beforeEach(() => {
+            feed = new CallFeed({
+                client,
+                roomId: "room1",
+                userId: "user1",
+                // @ts-ignore Mock
+                stream: new MockMediaStream("stream1"),
+                purpose: SDPStreamMetadataPurpose.Usermedia,
+                audioMuted: false,
+                videoMuted: false,
+            });
        });
-        feed.on(CallFeedEvent.NewStream, feedNewStreamCallback);

-        const replacementStream = new MockMediaStream("stream2");
-        // @ts-ignore Mock
-        feed.setNewStream(replacementStream);
-        expect(feedNewStreamCallback).toHaveBeenCalledWith(replacementStream);
-        expect(feed.stream).toBe(replacementStream);
+        describe("muting by default", () => {
+            it("should mute audio by default", () => {
+                expect(feed.isAudioMuted()).toBeTruthy();
+            });

-        feedNewStreamCallback.mockReset();
+            it("should mute video by default", () => {
+                expect(feed.isVideoMuted()).toBeTruthy();
+            });
+        });

-        replacementStream.addTrack(new MockMediaStreamTrack("track_id", "audio"));
-        expect(feedNewStreamCallback).toHaveBeenCalledWith(replacementStream);
+        describe("muting after adding a track", () => {
+            it("should un-mute audio", () => {
+                // @ts-ignore Mock
+                feed.stream.addTrack(new MockMediaStreamTrack("track", "audio", true));
+                expect(feed.isAudioMuted()).toBeFalsy();
+            });
+
+            it("should un-mute video", () => {
+                // @ts-ignore Mock
+                feed.stream.addTrack(new MockMediaStreamTrack("track", "video", true));
+                expect(feed.isVideoMuted()).toBeFalsy();
+            });
+        });
+
+        describe("muting after calling setAudioVideoMuted()", () => {
+            it("should mute audio by default ", () => {
+                // @ts-ignore Mock
+                feed.stream.addTrack(new MockMediaStreamTrack("track", "audio", true));
+                feed.setAudioVideoMuted(true, false);
+                expect(feed.isAudioMuted()).toBeTruthy();
+            });
+
+            it("should mute video by default", () => {
+                // @ts-ignore Mock
+                feed.stream.addTrack(new MockMediaStreamTrack("track", "video", true));
+                feed.setAudioVideoMuted(false, true);
+                expect(feed.isVideoMuted()).toBeTruthy();
+            });
+        });
    });
 });
@@ -17,5 +17,9 @@ limitations under the License.
 export enum ReceiptType {
    Read = "m.read",
    FullyRead = "m.fully_read",
-    ReadPrivate = "org.matrix.msc2285.read.private"
+    ReadPrivate = "m.read.private",
+    /**
+     * @deprecated Please use the ReadPrivate type when possible. This value may be removed at any time without notice.
+     */
+    UnstableReadPrivate = "org.matrix.msc2285.read.private",
 }
@@ -113,7 +113,7 @@ export interface IRoomDirectoryOptions {
    since?: string;
    filter?: {
        generic_search_term?: string;
-        "org.matrix.msc3827.room_types"?: Array<RoomType | null>;
+        room_types?: Array<RoomType | null>;
    };
    include_all_networks?: boolean;
    third_party_instance_id?: string;
@@ -24,7 +24,16 @@ import { ListenerMap, TypedEventEmitter } from "./models/typed-event-emitter";
 export class ReEmitter {
    constructor(private readonly target: EventEmitter) {}

+    // Map from emitter to event name to re-emitter
+    private reEmitters = new Map<EventEmitter, Map<string, (...args: any[]) => void>>();
+
    public reEmit(source: EventEmitter, eventNames: string[]): void {
+        let reEmittersByEvent = this.reEmitters.get(source);
+        if (!reEmittersByEvent) {
+            reEmittersByEvent = new Map();
+            this.reEmitters.set(source, reEmittersByEvent);
+        }
+
        for (const eventName of eventNames) {
            // We include the source as the last argument for event handlers which may need it,
            // such as read receipt listeners on the client class which won't have the context
@@ -44,8 +53,21 @@ export class ReEmitter {
                this.target.emit(eventName, ...args, source);
            };
            source.on(eventName, forSource);
+            reEmittersByEvent.set(eventName, forSource);
        }
    }
+
+    public stopReEmitting(source: EventEmitter, eventNames: string[]): void {
+        const reEmittersByEvent = this.reEmitters.get(source);
+        if (!reEmittersByEvent) return; // We were never re-emitting these events in the first place
+
+        for (const eventName of eventNames) {
+            source.off(eventName, reEmittersByEvent.get(eventName));
+            reEmittersByEvent.delete(eventName);
+        }
+
+        if (reEmittersByEvent.size === 0) this.reEmitters.delete(source);
+    }
 }

 export class TypedReEmitter<
@@ -62,4 +84,11 @@ export class TypedReEmitter<
    ): void {
        super.reEmit(source, eventNames);
    }
+
+    public stopReEmitting<ReEmittedEvents extends string, T extends Events & ReEmittedEvents>(
+        source: TypedEventEmitter<ReEmittedEvents, any>,
+        eventNames: T[],
+    ): void {
+        super.stopReEmitting(source, eventNames);
+    }
 }
@@ -0,0 +1,125 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { logger } from "./logger";
+import { MatrixClient } from "./matrix";
+import { IndexedToDeviceBatch, ToDeviceBatch, ToDeviceBatchWithTxnId, ToDevicePayload } from "./models/ToDeviceMessage";
+import { MatrixScheduler } from "./scheduler";
+
+const MAX_BATCH_SIZE = 20;
+
+/**
+ * Maintains a queue of outgoing to-device messages, sending them
+ * as soon as the homeserver is reachable.
+ */
+export class ToDeviceMessageQueue {
+    private sending = false;
+    private running = true;
+    private retryTimeout: number = null;
+    private retryAttempts = 0;
+
+    constructor(private client: MatrixClient) {
+    }
+
+    public start(): void {
+        this.running = true;
+        this.sendQueue();
+    }
+
+    public stop(): void {
+        this.running = false;
+        if (this.retryTimeout !== null) clearTimeout(this.retryTimeout);
+        this.retryTimeout = null;
+    }
+
+    public async queueBatch(batch: ToDeviceBatch): Promise<void> {
+        const batches: ToDeviceBatchWithTxnId[] = [];
+        for (let i = 0; i < batch.batch.length; i += MAX_BATCH_SIZE) {
+            batches.push({
+                eventType: batch.eventType,
+                batch: batch.batch.slice(i, i + MAX_BATCH_SIZE),
+                txnId: this.client.makeTxnId(),
+            });
+        }
+
+        await this.client.store.saveToDeviceBatches(batches);
+        this.sendQueue();
+    }
+
+    public sendQueue = async (): Promise<void> => {
+        if (this.retryTimeout !== null) clearTimeout(this.retryTimeout);
+        this.retryTimeout = null;
+
+        if (this.sending || !this.running) return;
+
+        logger.debug("Attempting to send queued to-device messages");
+
+        this.sending = true;
+        let headBatch;
+        try {
+            while (this.running) {
+                headBatch = await this.client.store.getOldestToDeviceBatch();
+                if (headBatch === null) break;
+                await this.sendBatch(headBatch);
+                await this.client.store.removeToDeviceBatch(headBatch.id);
+                this.retryAttempts = 0;
+            }
+
+            // Make sure we're still running after the async tasks: if not, stop.
+            if (!this.running) return;
+
+            logger.debug("All queued to-device messages sent");
+        } catch (e) {
+            ++this.retryAttempts;
+            // eslint-disable-next-line @typescript-eslint/naming-convention
+            // eslint-disable-next-line new-cap
+            const retryDelay = MatrixScheduler.RETRY_BACKOFF_RATELIMIT(null, this.retryAttempts, e);
+            if (retryDelay === -1) {
+                // the scheduler function doesn't differentiate between fatal errors and just getting
+                // bored and giving up for now
+                if (Math.floor(e.httpStatus / 100) === 4) {
+                    logger.error("Fatal error when sending to-device message - dropping to-device batch!", e);
+                    await this.client.store.removeToDeviceBatch(headBatch.id);
+                } else {
+                    logger.info("Automatic retry limit reached for to-device messages.");
+                }
+                return;
+            }
+
+            logger.info(`Failed to send batch of to-device messages. Will retry in ${retryDelay}ms`, e);
+            this.retryTimeout = setTimeout(this.sendQueue, retryDelay);
+        } finally {
+            this.sending = false;
+        }
+    };
+
+    /**
+     * Attempts to send a batch of to-device messages.
+     */
+    private async sendBatch(batch: IndexedToDeviceBatch): Promise<void> {
+        const contentMap: Record<string, Record<string, ToDevicePayload>> = {};
+        for (const item of batch.batch) {
+            if (!contentMap[item.userId]) {
+                contentMap[item.userId] = {};
+            }
+            contentMap[item.userId][item.deviceId] = item.payload;
+        }
+
+        logger.info(`Sending batch of ${batch.batch.length} to-device messages with ID ${batch.id}`);
+
+        await this.client.sendToDevice(batch.eventType, contentMap, batch.txnId);
+    }
+}
@@ -17,6 +17,8 @@ limitations under the License.

 /** @module auto-discovery */

+import { ServerResponse } from "http";
+
 import { IClientWellKnown, IWellKnownConfig } from "./client";
 import { logger } from './logger';

@@ -409,39 +411,41 @@ export class AutoDiscovery {
     * @return {Promise<object>} Resolves to the returned state.
     * @private
     */
-    private static fetchWellKnownObject(url: string): Promise<IWellKnownConfig> {
-        return new Promise(function(resolve) {
+    private static fetchWellKnownObject(uri: string): Promise<IWellKnownConfig> {
+        return new Promise((resolve) => {
            // eslint-disable-next-line
            const request = require("./matrix").getRequest();
            if (!request) throw new Error("No request library available");
            request(
-                { method: "GET", uri: url, timeout: 5000 },
-                (err, response, body) => {
-                    if (err || response &&
-                        (response.statusCode < 200 || response.statusCode >= 300)
-                    ) {
-                        let action = AutoDiscoveryAction.FAIL_PROMPT;
-                        let reason = (err ? err.message : null) || "General failure";
-                        if (response && response.statusCode === 404) {
-                            action = AutoDiscoveryAction.IGNORE;
-                            reason = AutoDiscovery.ERROR_MISSING_WELLKNOWN;
-                        }
-                        resolve({ raw: {}, action: action, reason: reason, error: err });
-                        return;
+                { method: "GET", uri, timeout: 5000 },
+                (error: Error, response: ServerResponse, body: string) => {
+                    if (error || response?.statusCode < 200 || response?.statusCode >= 300) {
+                        const result = { error, raw: {} };
+                        return resolve(response?.statusCode === 404
+                            ? {
+                                ...result,
+                                action: AutoDiscoveryAction.IGNORE,
+                                reason: AutoDiscovery.ERROR_MISSING_WELLKNOWN,
+                            } : {
+                                ...result,
+                                action: AutoDiscoveryAction.FAIL_PROMPT,
+                                reason: error?.message || "General failure",
+                            });
                    }

                    try {
-                        resolve({ raw: JSON.parse(body), action: AutoDiscoveryAction.SUCCESS });
-                    } catch (e) {
-                        let reason = AutoDiscovery.ERROR_INVALID;
-                        if (e.name === "SyntaxError") {
-                            reason = AutoDiscovery.ERROR_INVALID_JSON;
-                        }
-                        resolve({
+                        return resolve({
+                            raw: JSON.parse(body),
+                            action: AutoDiscoveryAction.SUCCESS,
+                        });
+                    } catch (err) {
+                        return resolve({
+                            error: err,
                            raw: {},
                            action: AutoDiscoveryAction.FAIL_PROMPT,
-                            reason: reason,
-                            error: e,
+                            reason: err?.name === "SyntaxError"
+                                ? AutoDiscovery.ERROR_INVALID_JSON
+                                : AutoDiscovery.ERROR_INVALID,
                        });
                    }
                },
@@ -1,5 +1,5 @@
 /*
-Copyright 2015-2021 The Matrix.org Foundation C.I.C.
+Copyright 2015-2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -42,7 +42,8 @@ import { IActionsObject, PushProcessor } from "./pushprocessor";
 import { AutoDiscovery, AutoDiscoveryAction } from "./autodiscovery";
 import * as olmlib from "./crypto/olmlib";
 import { decodeBase64, encodeBase64 } from "./crypto/olmlib";
-import { IExportedDevice as IOlmDevice } from "./crypto/OlmDevice";
+import { IExportedDevice as IExportedOlmDevice } from "./crypto/OlmDevice";
+import { IOlmDevice } from "./crypto/algorithms/megolm";
 import { TypedReEmitter } from './ReEmitter';
 import { IRoomEncryption, RoomList } from './crypto/RoomList';
 import { logger } from './logger';
@@ -136,7 +137,7 @@ import { VerificationRequest } from "./crypto/verification/request/VerificationR
 import { VerificationBase as Verification } from "./crypto/verification/Base";
 import * as ContentHelpers from "./content-helpers";
 import { CrossSigningInfo, DeviceTrustLevel, ICacheCallbacks, UserTrustLevel } from "./crypto/CrossSigning";
-import { Room } from "./models/room";
+import { Room, RoomNameState } from "./models/room";
 import {
    IAddThreePidOnlyBody,
    IBindThreePidBody,
@@ -190,8 +191,12 @@ import { MediaHandler } from "./webrtc/mediaHandler";
 import { IRefreshTokenResponse } from "./@types/auth";
 import { TypedEventEmitter } from "./models/typed-event-emitter";
 import { ReceiptType } from "./@types/read_receipts";
+import { MSC3575SlidingSyncRequest, MSC3575SlidingSyncResponse, SlidingSync } from "./sliding-sync";
+import { SlidingSyncSdk } from "./sliding-sync-sdk";
 import { Thread, THREAD_RELATION_TYPE } from "./models/thread";
 import { MBeaconInfoEventContent, M_BEACON_INFO } from "./@types/beacon";
+import { ToDeviceMessageQueue } from "./ToDeviceMessageQueue";
+import { ToDeviceBatch } from "./models/ToDeviceMessage";

 export type Store = IStore;

@@ -204,7 +209,7 @@ const CAPABILITIES_CACHE_MS = 21600000; // 6 hours - an arbitrary value
 const TURN_CHECK_INTERVAL = 10 * 60 * 1000; // poll for turn credentials every 10 minutes

 interface IExportedDevice {
-    olmDevice: IOlmDevice;
+    olmDevice: IExportedOlmDevice;
    userId: string;
    deviceId: string;
 }
@@ -339,6 +344,12 @@ export interface ICreateClientOpts {
    fallbackICEServerAllowed?: boolean;

    cryptoCallbacks?: ICryptoCallbacks;
+
+    /**
+     * Method to generate room names for empty rooms and rooms names based on membership.
+     * Defaults to a built-in English handler with basic pluralisation.
+     */
+    roomNameGenerator?: (roomId: string, state: RoomNameState) => string | null;
 }

 export interface IMatrixClientCreateOpts extends ICreateClientOpts {
@@ -385,8 +396,7 @@ export interface IStartClientOpts {
    pollTimeout?: number;

    /**
-     * The filter to apply to /sync calls. This will override the opts.initialSyncLimit, which would
-     * normally result in a timeline limit filter.
+     * The filter to apply to /sync calls.
     */
    filter?: Filter;

@@ -411,6 +421,11 @@ export interface IStartClientOpts {
     * @experimental
     */
    experimentalThreadSupport?: boolean;
+
+    /**
+     * @experimental
+     */
+     slidingSync?: SlidingSync;
 }

 export interface IStoredClientOpts extends IStartClientOpts {
@@ -495,7 +510,7 @@ interface ITurnServerResponse {
    ttl: number;
 }

-interface ITurnServer {
+export interface ITurnServer {
    urls: string[];
    username: string;
    credential: string;
@@ -780,6 +795,8 @@ export enum ClientEvent {
    DeleteRoom = "deleteRoom",
    SyncUnexpectedError = "sync.unexpectedError",
    ClientWellKnown = "WellKnown.client",
+    TurnServers = "turnServers",
+    TurnServersError = "turnServers.error",
 }

 type RoomEvents = RoomEvent.Name
@@ -850,6 +867,8 @@ export type ClientEventHandlerMap = {
    [ClientEvent.DeleteRoom]: (roomId: string) => void;
    [ClientEvent.SyncUnexpectedError]: (error: Error) => void;
    [ClientEvent.ClientWellKnown]: (data: IClientWellKnown) => void;
+    [ClientEvent.TurnServers]: (servers: ITurnServer[]) => void;
+    [ClientEvent.TurnServersError]: (error: Error, fatal: boolean) => void;
 } & RoomEventHandlerMap
    & RoomStateEventHandlerMap
    & CryptoEventHandlerMap
@@ -903,7 +922,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    protected verificationMethods: VerificationMethod[];
    protected fallbackICEServerAllowed = false;
    protected roomList: RoomList;
-    protected syncApi: SyncApi;
+    protected syncApi: SlidingSyncSdk | SyncApi;
+    public roomNameGenerator?: ICreateClientOpts["roomNameGenerator"];
    public pushRules: IPushRules;
    protected syncLeftRoomsPromise: Promise<Room[]>;
    protected syncedLeftRooms = false;
@@ -926,12 +946,14 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    protected clientWellKnownPromise: Promise<IClientWellKnown>;
    protected turnServers: ITurnServer[] = [];
    protected turnServersExpiry = 0;
-    protected checkTurnServersIntervalID: ReturnType<typeof setInterval>;
-    protected exportedOlmDeviceToImport: IOlmDevice;
+    protected checkTurnServersIntervalID: ReturnType<typeof setInterval> | null = null;
+    protected exportedOlmDeviceToImport: IExportedOlmDevice;
    protected txnCtr = 0;
    protected mediaHandler = new MediaHandler(this);
    protected pendingEventEncryption = new Map<string, Promise<void>>();

+    private toDeviceMessageQueue: ToDeviceMessageQueue;
+
    constructor(opts: IMatrixClientCreateOpts) {
        super();

@@ -1025,6 +1047,9 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        // we still want to know which rooms are encrypted even if crypto is disabled:
        // we don't want to start sending unencrypted events to them.
        this.roomList = new RoomList(this.cryptoStore);
+        this.roomNameGenerator = opts.roomNameGenerator;
+
+        this.toDeviceMessageQueue = new ToDeviceMessageQueue(this);

        // The SDK doesn't really provide a clean way for events to recalculate the push
        // actions for themselves, so we have to kinda help them out when they are encrypted.
@@ -1070,11 +1095,12 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
                // Figure out if we've read something or if it's just informational
                const content = event.getContent();
                const isSelf = Object.keys(content).filter(eid => {
-                    const read = content[eid][ReceiptType.Read];
-                    if (read && Object.keys(read).includes(this.getUserId())) return true;
+                    for (const [key, value] of Object.entries(content[eid])) {
+                        if (!utils.isSupportedReceiptType(key)) continue;
+                        if (!value) continue;

-                    const readPrivate = content[eid][ReceiptType.ReadPrivate];
-                    if (readPrivate && Object.keys(readPrivate).includes(this.getUserId())) return true;
+                        if (Object.keys(value).includes(this.getUserId())) return true;
+                    }

                    return false;
                }).length > 0;
@@ -1176,7 +1202,11 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
            }
            return this.canResetTimelineCallback(roomId);
        };
-        this.syncApi = new SyncApi(this, this.clientOpts);
+        if (this.clientOpts.slidingSync) {
+            this.syncApi = new SlidingSyncSdk(this.clientOpts.slidingSync, this, this.clientOpts);
+        } else {
+            this.syncApi = new SyncApi(this, this.clientOpts);
+        }
        this.syncApi.sync();

        if (this.clientOpts.clientWellKnownPollPeriod !== undefined) {
@@ -1185,6 +1215,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
            }, 1000 * this.clientOpts.clientWellKnownPollPeriod);
            this.fetchClientWellKnown();
        }
+
+        this.toDeviceMessageQueue.start();
    }

    /**
@@ -1209,9 +1241,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        this.callEventHandler = null;

        global.clearInterval(this.checkTurnServersIntervalID);
+        this.checkTurnServersIntervalID = null;
+
        if (this.clientWellKnownIntervalID !== undefined) {
            global.clearInterval(this.clientWellKnownIntervalID);
        }
+
+        this.toDeviceMessageQueue.stop();
    }

    /**
@@ -1550,9 +1586,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    /**
     * Retry a backed off syncing request immediately. This should only be used when
     * the user <b>explicitly</b> attempts to retry their lost connection.
+     * Will also retry any outbound to-device messages currently in the queue to be sent
+     * (retries of regular outgoing events are handled separately, per-event).
     * @return {boolean} True if this resulted in a request being retried.
     */
    public retryImmediately(): boolean {
+        // don't await for this promise: we just want to kick it off
+        this.toDeviceMessageQueue.sendQueue();
        return this.syncApi.retryImmediately();
    }

@@ -2533,6 +2573,30 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        return this.roomList.isRoomEncrypted(roomId);
    }

+    /**
+     * Encrypts and sends a given object via Olm to-device messages to a given
+     * set of devices.
+     *
+     * @param {object[]} userDeviceInfoArr
+     *   mapping from userId to deviceInfo
+     *
+     * @param {object} payload fields to include in the encrypted payload
+     *      *
+     * @return {Promise<{contentMap, deviceInfoByDeviceId}>} Promise which
+     *     resolves once the message has been encrypted and sent to the given
+     *     userDeviceMap, and returns the { contentMap, deviceInfoByDeviceId }
+     *     of the successfully sent messages.
+     */
+    public encryptAndSendToDevices(
+        userDeviceInfoArr: IOlmDevice<DeviceInfo>[],
+        payload: object,
+    ): Promise<void> {
+        if (!this.crypto) {
+            throw new Error("End-to-End encryption disabled");
+        }
+        return this.crypto.encryptAndSendToDevices(userDeviceInfoArr, payload);
+    }
+
    /**
     * Forces the current outbound group session to be discarded such
     * that another one will be created next time an event is sent.
@@ -3489,7 +3553,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    }

    /**
-     * Resend an event.
+     * Resend an event. Will also retry any to-device messages waiting to be sent.
     * @param {MatrixEvent} event The event to resend.
     * @param {Room} room Optional. The room the event is in. Will update the
     * timeline entry if provided.
@@ -3497,6 +3561,9 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     * @return {module:http-api.MatrixError} Rejects: with an error response.
     */
    public resendEvent(event: MatrixEvent, room: Room): Promise<ISendEventResponse> {
+        // also kick the to-device queue to retry
+        this.toDeviceMessageQueue.sendQueue();
+
        this.updatePendingEventStatus(room, event, EventStatus.SENDING);
        return this.encryptAndSendEvent(room, event);
    }
@@ -4601,7 +4668,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
            room?.addLocalEchoReceipt(this.credentials.userId, rpEvent, ReceiptType.ReadPrivate);
        }

-        return this.setRoomReadMarkersHttpRequest(roomId, rmEventId, rrEventId, rpEventId);
+        return await this.setRoomReadMarkersHttpRequest(roomId, rmEventId, rrEventId, rpEventId);
    }

    /**
@@ -5874,6 +5941,9 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        // There can be only room-kind push rule per room
        // and its id is the room id.
        if (this.pushRules) {
+            if (!this.pushRules[scope] || !this.pushRules[scope].room) {
+                return;
+            }
            for (let i = 0; i < this.pushRules[scope].room.length; i++) {
                const rule = this.pushRules[scope].room[i];
                if (rule.rule_id === roomId) {
@@ -6278,14 +6348,18 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    }

    /**
-     * Get the unix timestamp (in seconds) at which the current
+     * Get the unix timestamp (in milliseconds) at which the current
     * TURN credentials (from getTurnServers) expire
-     * @return {number} The expiry timestamp, in seconds, or null if no credentials
+     * @return {number} The expiry timestamp, in milliseconds, or null if no credentials
     */
    public getTurnServersExpiry(): number | null {
        return this.turnServersExpiry;
    }

+    public get pollingTurnServers(): boolean {
+        return this.checkTurnServersIntervalID !== null;
+    }
+
    // XXX: Intended private, used in code.
    public async checkTurnServers(): Promise<boolean> {
        if (!this.canSupportVoip) {
@@ -6313,17 +6387,21 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
                    // The TTL is in seconds but we work in ms
                    this.turnServersExpiry = Date.now() + (res.ttl * 1000);
                    credentialsGood = true;
+                    this.emit(ClientEvent.TurnServers, this.turnServers);
                }
            } catch (err) {
                logger.error("Failed to get TURN URIs", err);
-                // If we get a 403, there's no point in looping forever.
                if (err.httpStatus === 403) {
+                    // We got a 403, so there's no point in looping forever.
                    logger.info("TURN access unavailable for this account: stopping credentials checks");
                    if (this.checkTurnServersIntervalID !== null) global.clearInterval(this.checkTurnServersIntervalID);
                    this.checkTurnServersIntervalID = null;
+                    this.emit(ClientEvent.TurnServersError, err, true); // fatal
+                } else {
+                    // otherwise, if we failed for whatever reason, try again the next time we're called.
+                    this.emit(ClientEvent.TurnServersError, err, false); // non-fatal
                }
            }
-            // otherwise, if we failed for whatever reason, try again the next time we're called.
        }

        return credentialsGood;
@@ -7430,7 +7508,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     * don't want other users to see the read receipts. This is experimental. Optional.
     * @return {Promise} Resolves: the empty object, {}.
     */
-    public setRoomReadMarkersHttpRequest(
+    public async setRoomReadMarkersHttpRequest(
        roomId: string,
        rmEventId: string,
        rrEventId: string,
@@ -7443,9 +7521,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        const content = {
            [ReceiptType.FullyRead]: rmEventId,
            [ReceiptType.Read]: rrEventId,
-            [ReceiptType.ReadPrivate]: rpEventId,
        };

+        const privateField = await utils.getPrivateReadReceiptField(this);
+        if (privateField) {
+            content[privateField] = rpEventId;
+        }
+
        return this.http.authedRequest(undefined, Method.Post, path, undefined, content);
    }

@@ -8680,7 +8762,10 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
    }

    /**
-     * Send an event to a specific list of devices
+     * Send an event to a specific list of devices.
+     * This is a low-level API that simply wraps the HTTP API
+     * call to send to-device messages. We recommend using
+     * queueToDevice() which is a higher level API.
     *
     * @param {string} eventType  type of event to send
     * @param {Object.<string, Object<string, Object>>} contentMap
@@ -8712,6 +8797,17 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        return this.http.authedRequest(undefined, Method.Put, path, undefined, body);
    }

+    /**
+     * Sends events directly to specific devices using Matrix's to-device
+     * messaging system. The batch will be split up into appropriately sized
+     * batches for sending and stored in the store so they can be retried
+     * later if they fail to send. Retries will happen automatically.
+     * @param batch The to-device messages to send
+     */
+    public queueToDevice(batch: ToDeviceBatch): Promise<void> {
+        return this.toDeviceMessageQueue.queueBatch(batch);
+    }
+
    /**
     * Get the third party protocols that can be reached using
     * this HS
@@ -8908,6 +9004,41 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
        return new MSC3089TreeSpace(this, roomId);
    }

+    /**
+     * Perform a single MSC3575 sliding sync request.
+     * @param {MSC3575SlidingSyncRequest} req The request to make.
+     * @param {string} proxyBaseUrl The base URL for the sliding sync proxy.
+     * @returns {MSC3575SlidingSyncResponse} The sliding sync response, or a standard error.
+     * @throws on non 2xx status codes with an object with a field "httpStatus":number.
+     */
+    public slidingSync(
+        req: MSC3575SlidingSyncRequest, proxyBaseUrl?: string,
+    ): IAbortablePromise<MSC3575SlidingSyncResponse> {
+        const qps: Record<string, any> = {};
+        if (req.pos) {
+            qps.pos = req.pos;
+            delete req.pos;
+        }
+        if (req.timeout) {
+            qps.timeout = req.timeout;
+            delete req.timeout;
+        }
+        const clientTimeout = req.clientTimeout;
+        delete req.clientTimeout;
+        return this.http.authedRequest<MSC3575SlidingSyncResponse>(
+            undefined,
+            Method.Post,
+            "/sync",
+            qps,
+            req,
+            {
+                prefix: "/_matrix/client/unstable/org.matrix.msc3575",
+                baseUrl: proxyBaseUrl,
+                localTimeoutMs: clientTimeout,
+            },
+        );
+    }
+
    /**
     * @experimental
     */
@@ -247,7 +247,7 @@ export const makeBeaconInfoContent: MakeBeaconInfoContent = (
 });

 export type BeaconInfoState = MBeaconInfoContent & {
-    assetType: LocationAssetType;
+    assetType?: LocationAssetType;
    timestamp: number;
 };
 /**
@@ -255,14 +255,14 @@ export type BeaconInfoState = MBeaconInfoContent & {
 */
 export const parseBeaconInfoContent = (content: MBeaconInfoEventContent): BeaconInfoState => {
    const { description, timeout, live } = content;
-    const { type: assetType } = M_ASSET.findIn<MAssetContent>(content);
    const timestamp = M_TIMESTAMP.findIn<number>(content);
+    const asset = M_ASSET.findIn<MAssetContent>(content);

    return {
        description,
        timeout,
        live,
-        assetType,
+        assetType: asset?.type,
        timestamp,
    };
 };
@@ -36,9 +36,9 @@ import * as utils from "./utils";
 export function getHttpUriForMxc(
    baseUrl: string,
    mxc: string,
-    width: number,
-    height: number,
-    resizeMethod: string,
+    width?: number,
+    height?: number,
+    resizeMethod?: string,
    allowDirectLinks = false,
 ): string {
    if (typeof mxc !== "string" || !mxc) {
@@ -34,7 +34,7 @@ import { IRoomEncryption } from "../RoomList";
 *
 * @type {Object.<string, function(new: module:crypto/algorithms/base.EncryptionAlgorithm)>}
 */
-export const ENCRYPTION_CLASSES: Record<string, new (params: IParams) => EncryptionAlgorithm> = {};
+export const ENCRYPTION_CLASSES = new Map<string, new (params: IParams) => EncryptionAlgorithm>();

 type DecryptionClassParams = Omit<IParams, "deviceId" | "config">;

@@ -44,7 +44,7 @@ type DecryptionClassParams = Omit<IParams, "deviceId" | "config">;
 *
 * @type {Object.<string, function(new: module:crypto/algorithms/base.DecryptionAlgorithm)>}
 */
-export const DECRYPTION_CLASSES: Record<string, new (params: DecryptionClassParams) => DecryptionAlgorithm> = {};
+export const DECRYPTION_CLASSES = new Map<string, new (params: DecryptionClassParams) => DecryptionAlgorithm>();

 export interface IParams {
    userId: string;
@@ -297,6 +297,6 @@ export function registerAlgorithm(
    encryptor: new (params: IParams) => EncryptionAlgorithm,
    decryptor: new (params: Omit<IParams, "deviceId">) => DecryptionAlgorithm,
 ): void {
-    ENCRYPTION_CLASSES[algorithm] = encryptor;
-    DECRYPTION_CLASSES[algorithm] = decryptor;
+    ENCRYPTION_CLASSES.set(algorithm, encryptor);
+    DECRYPTION_CLASSES.set(algorithm, decryptor);
 }
@@ -606,96 +606,25 @@ class MegolmEncryption extends EncryptionAlgorithm {
    private encryptAndSendKeysToDevices(
        session: OutboundSessionInfo,
        chainIndex: number,
-        userDeviceMap: IOlmDevice[],
+        devices: IOlmDevice[],
        payload: IPayload,
    ): Promise<void> {
-        const contentMap: Record<string, Record<string, IEncryptedContent>> = {};
-        // Map from userId to a map of deviceId to deviceInfo
-        const deviceInfoByUserIdAndDeviceId = new Map<string, Map<string, DeviceInfo>>();
-
-        const promises: Promise<unknown>[] = [];
-        for (let i = 0; i < userDeviceMap.length; i++) {
-            const encryptedContent: IEncryptedContent = {
-                algorithm: olmlib.OLM_ALGORITHM,
-                sender_key: this.olmDevice.deviceCurve25519Key,
-                ciphertext: {},
-            };
-            const val = userDeviceMap[i];
-            const userId = val.userId;
-            const deviceInfo = val.deviceInfo;
-            const deviceId = deviceInfo.deviceId;
-
-            // Assign to temp value to make type-checking happy
-            let userIdDeviceInfo = deviceInfoByUserIdAndDeviceId.get(userId);
-
-            if (userIdDeviceInfo === undefined) {
-                userIdDeviceInfo = new Map<string, DeviceInfo>();
-
-                deviceInfoByUserIdAndDeviceId.set(userId, userIdDeviceInfo);
+        return this.crypto.encryptAndSendToDevices(
+            devices,
+            payload,
+        ).then(() => {
+            // store that we successfully uploaded the keys of the current slice
+            for (const device of devices) {
+                session.markSharedWithDevice(
+                    device.userId,
+                    device.deviceInfo.deviceId,
+                    device.deviceInfo.getIdentityKey(),
+                    chainIndex,
+                );
            }
-
-            // We hold by reference, this updates deviceInfoByUserIdAndDeviceId[userId]
-            userIdDeviceInfo.set(deviceId, deviceInfo);
-
-            if (!contentMap[userId]) {
-                contentMap[userId] = {};
-            }
-            contentMap[userId][deviceId] = encryptedContent;
-
-            promises.push(
-                olmlib.encryptMessageForDevice(
-                    encryptedContent.ciphertext,
-                    this.userId,
-                    this.deviceId,
-                    this.olmDevice,
-                    userId,
-                    deviceInfo,
-                    payload,
-                ),
-            );
-        }
-
-        return Promise.all(promises).then(() => {
-            // prune out any devices that encryptMessageForDevice could not encrypt for,
-            // in which case it will have just not added anything to the ciphertext object.
-            // There's no point sending messages to devices if we couldn't encrypt to them,
-            // since that's effectively a blank message.
-            for (const userId of Object.keys(contentMap)) {
-                for (const deviceId of Object.keys(contentMap[userId])) {
-                    if (Object.keys(contentMap[userId][deviceId].ciphertext).length === 0) {
-                        logger.log(
-                            "No ciphertext for device " +
-                            userId + ":" + deviceId + ": pruning",
-                        );
-                        delete contentMap[userId][deviceId];
-                    }
-                }
-                // No devices left for that user? Strip that too.
-                if (Object.keys(contentMap[userId]).length === 0) {
-                    logger.log("Pruned all devices for user " + userId);
-                    delete contentMap[userId];
-                }
-            }
-
-            // Is there anything left?
-            if (Object.keys(contentMap).length === 0) {
-                logger.log("No users left to send to: aborting");
-                return;
-            }
-
-            return this.baseApis.sendToDevice("m.room.encrypted", contentMap).then(() => {
-                // store that we successfully uploaded the keys of the current slice
-                for (const userId of Object.keys(contentMap)) {
-                    for (const deviceId of Object.keys(contentMap[userId])) {
-                        session.markSharedWithDevice(
-                            userId,
-                            deviceId,
-                            deviceInfoByUserIdAndDeviceId.get(userId).get(deviceId).getIdentityKey(),
-                            chainIndex,
-                        );
-                    }
-                }
-            });
+        }).catch((error) => {
+            logger.error("failed to encryptAndSendToDevices", error);
+            throw error;
        });
    }

@@ -738,7 +667,6 @@ class MegolmEncryption extends EncryptionAlgorithm {
            contentMap[userId][deviceId] = message;
        }

-        await this.baseApis.sendToDevice("org.matrix.room_key.withheld", contentMap);
        await this.baseApis.sendToDevice("m.room_key.withheld", contentMap);

        // record the fact that we notified these blocked devices
@@ -1263,7 +1191,7 @@ class MegolmEncryption extends EncryptionAlgorithm {
 class MegolmDecryption extends DecryptionAlgorithm {
    // events which we couldn't decrypt due to unknown sessions / indexes: map from
    // senderKey|sessionId to Set of MatrixEvents
-    private pendingEvents: Record<string, Map<string, Set<MatrixEvent>>> = {};
+    private pendingEvents = new Map<string, Map<string, Set<MatrixEvent>>>();

    // this gets stubbed out by the unit tests.
    private olmlib = olmlib;
@@ -1415,10 +1343,10 @@ class MegolmDecryption extends DecryptionAlgorithm {
        const content = event.getWireContent();
        const senderKey = content.sender_key;
        const sessionId = content.session_id;
-        if (!this.pendingEvents[senderKey]) {
-            this.pendingEvents[senderKey] = new Map();
+        if (!this.pendingEvents.has(senderKey)) {
+            this.pendingEvents.set(senderKey, new Map<string, Set<MatrixEvent>>());
        }
-        const senderPendingEvents = this.pendingEvents[senderKey];
+        const senderPendingEvents = this.pendingEvents.get(senderKey);
        if (!senderPendingEvents.has(sessionId)) {
            senderPendingEvents.set(sessionId, new Set());
        }
@@ -1436,7 +1364,7 @@ class MegolmDecryption extends DecryptionAlgorithm {
        const content = event.getWireContent();
        const senderKey = content.sender_key;
        const sessionId = content.session_id;
-        const senderPendingEvents = this.pendingEvents[senderKey];
+        const senderPendingEvents = this.pendingEvents.get(senderKey);
        const pendingEvents = senderPendingEvents?.get(sessionId);
        if (!pendingEvents) {
            return;
@@ -1447,7 +1375,7 @@ class MegolmDecryption extends DecryptionAlgorithm {
            senderPendingEvents.delete(sessionId);
        }
        if (senderPendingEvents.size === 0) {
-            delete this.pendingEvents[senderKey];
+            this.pendingEvents.delete(senderKey);
        }
    }

@@ -1783,7 +1711,7 @@ class MegolmDecryption extends DecryptionAlgorithm {
     * @return {Boolean} whether all messages were successfully decrypted
     */
    private async retryDecryption(senderKey: string, sessionId: string): Promise<boolean> {
-        const senderPendingEvents = this.pendingEvents[senderKey];
+        const senderPendingEvents = this.pendingEvents.get(senderKey);
        if (!senderPendingEvents) {
            return true;
        }
@@ -1804,16 +1732,16 @@ class MegolmDecryption extends DecryptionAlgorithm {
        }));

        // If decrypted successfully, they'll have been removed from pendingEvents
-        return !this.pendingEvents[senderKey]?.has(sessionId);
+        return !this.pendingEvents.get(senderKey)?.has(sessionId);
    }

    public async retryDecryptionFromSender(senderKey: string): Promise<boolean> {
-        const senderPendingEvents = this.pendingEvents[senderKey];
+        const senderPendingEvents = this.pendingEvents.get(senderKey);
        if (!senderPendingEvents) {
            return true;
        }

-        delete this.pendingEvents[senderKey];
+        this.pendingEvents.delete(senderKey);

        await Promise.all([...senderPendingEvents].map(async ([_sessionId, pending]) => {
            await Promise.all([...pending].map(async (ev) => {
@@ -1825,7 +1753,7 @@ class MegolmDecryption extends DecryptionAlgorithm {
            }));
        }));

-        return !this.pendingEvents[senderKey];
+        return !this.pendingEvents.has(senderKey);
    }

    public async sendSharedHistoryInboundSessions(devicesByUser: Record<string, DeviceInfo[]>): Promise<void> {
@@ -23,9 +23,11 @@ limitations under the License.

 import anotherjson from "another-json";

+import { EventType } from "../@types/event";
 import { TypedReEmitter } from '../ReEmitter';
 import { logger } from '../logger';
 import { IExportedDevice, OlmDevice } from "./OlmDevice";
+import { IOlmDevice } from "./algorithms/megolm";
 import * as olmlib from "./olmlib";
 import { DeviceInfoMap, DeviceList } from "./DeviceList";
 import { DeviceInfo, IDevice } from "./deviceinfo";
@@ -68,6 +70,7 @@ import { IStore } from "../store";
 import { Room, RoomEvent } from "../models/room";
 import { RoomMember, RoomMemberEvent } from "../models/room-member";
 import { EventStatus, IClearEvent, IEvent, MatrixEvent, MatrixEventEvent } from "../models/event";
+import { ToDeviceBatch } from "../models/ToDeviceMessage";
 import {
    ClientEvent,
    ICrossSigningKey,
@@ -201,6 +204,14 @@ export interface IRequestsMap {
    setRequestByChannel(channel: IVerificationChannel, request: VerificationRequest): void;
 }

+/* eslint-disable camelcase */
+export interface IEncryptedContent {
+    algorithm: string;
+    sender_key: string;
+    ciphertext: Record<string, string>;
+}
+/* eslint-enable camelcase */
+
 export enum CryptoEvent {
    DeviceVerificationChanged = "deviceVerificationChanged",
    UserTrustStatusChanged = "userTrustStatusChanged",
@@ -267,9 +278,9 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
    private oneTimeKeyCheckInProgress = false;

    // EncryptionAlgorithm instance for each room
-    private roomEncryptors: Record<string, EncryptionAlgorithm> = {};
+    private roomEncryptors = new Map<string, EncryptionAlgorithm>();
    // map from algorithm to DecryptionAlgorithm instance, for each room
-    private roomDecryptors: Record<string, Record<string, DecryptionAlgorithm>> = {};
+    private roomDecryptors = new Map<string, Map<string, DecryptionAlgorithm>>();

    private deviceKeys: Record<string, string> = {}; // type: key

@@ -411,7 +422,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
        this.deviceList.on(CryptoEvent.UserCrossSigningUpdated, this.onDeviceListUserCrossSigningUpdated);
        this.reEmitter.reEmit(this.deviceList, [CryptoEvent.DevicesUpdated, CryptoEvent.WillUpdateDevices]);

-        this.supportedAlgorithms = Object.keys(algorithms.DECRYPTION_CLASSES);
+        this.supportedAlgorithms = Array.from(algorithms.DECRYPTION_CLASSES.keys());

        this.outgoingRoomKeyRequestManager = new OutgoingRoomKeyRequestManager(
            baseApis, this.deviceId, this.cryptoStore,
@@ -2516,7 +2527,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     * This should not normally be necessary.
     */
    public forceDiscardSession(roomId: string): void {
-        const alg = this.roomEncryptors[roomId];
+        const alg = this.roomEncryptors.get(roomId);
        if (alg === undefined) throw new Error("Room not encrypted");
        if (alg.forceDiscardSession === undefined) {
            throw new Error("Room encryption algorithm doesn't support session discarding");
@@ -2569,7 +2580,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
        // the encryption event would appear in both.
        // If it's called more than twice though,
        // it signals a bug on client or server.
-        const existingAlg = this.roomEncryptors[roomId];
+        const existingAlg = this.roomEncryptors.get(roomId);
        if (existingAlg) {
            return;
        }
@@ -2583,7 +2594,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
            storeConfigPromise = this.roomList.setRoomEncryption(roomId, config);
        }

-        const AlgClass = algorithms.ENCRYPTION_CLASSES[config.algorithm];
+        const AlgClass = algorithms.ENCRYPTION_CLASSES.get(config.algorithm);
        if (!AlgClass) {
            throw new Error("Unable to encrypt with " + config.algorithm);
        }
@@ -2597,7 +2608,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
            roomId,
            config,
        });
-        this.roomEncryptors[roomId] = alg;
+        this.roomEncryptors.set(roomId, alg);

        if (storeConfigPromise) {
            await storeConfigPromise;
@@ -2629,7 +2640,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
    public trackRoomDevices(roomId: string): Promise<void> {
        const trackMembers = async () => {
            // not an encrypted room
-            if (!this.roomEncryptors[roomId]) {
+            if (!this.roomEncryptors.has(roomId)) {
                return;
            }
            const room = this.clientStore.getRoom(roomId);
@@ -2774,7 +2785,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     * @param {module:models/room} room the room the event is in
     */
    public prepareToEncrypt(room: Room): void {
-        const alg = this.roomEncryptors[room.roomId];
+        const alg = this.roomEncryptors.get(room.roomId);
        if (alg) {
            alg.prepareToEncrypt(room);
        }
@@ -2797,7 +2808,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap

        const roomId = event.getRoomId();

-        const alg = this.roomEncryptors[roomId];
+        const alg = this.roomEncryptors.get(roomId);
        if (!alg) {
            // MatrixClient has already checked that this room should be encrypted,
            // so this is an unexpected situation.
@@ -2859,7 +2870,10 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     */
    public async decryptEvent(event: MatrixEvent): Promise<IEventDecryptionResult> {
        if (event.isRedacted()) {
-            const redactionEvent = new MatrixEvent(event.getUnsigned().redacted_because);
+            const redactionEvent = new MatrixEvent({
+                room_id: event.getRoomId(),
+                ...event.getUnsigned().redacted_because,
+            });
            const decryptedEvent = await this.decryptEvent(redactionEvent);

            return {
@@ -3083,7 +3097,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
    private getTrackedE2eRooms(): Room[] {
        return this.clientStore.getRooms().filter((room) => {
            // check for rooms with encryption enabled
-            const alg = this.roomEncryptors[room.roomId];
+            const alg = this.roomEncryptors.get(room.roomId);
            if (!alg) {
                return false;
            }
@@ -3097,6 +3111,81 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
        });
    }

+    /**
+     * Encrypts and sends a given object via Olm to-device messages to a given
+     * set of devices.
+     * @param {object[]} userDeviceInfoArr the devices to send to
+     * @param {object} payload fields to include in the encrypted payload
+     * @return {Promise<{contentMap, deviceInfoByDeviceId}>} Promise which
+     *     resolves once the message has been encrypted and sent to the given
+     *     userDeviceMap, and returns the { contentMap, deviceInfoByDeviceId }
+     *     of the successfully sent messages.
+     */
+    public async encryptAndSendToDevices(
+        userDeviceInfoArr: IOlmDevice<DeviceInfo>[],
+        payload: object,
+    ): Promise<void> {
+        const toDeviceBatch: ToDeviceBatch = {
+            eventType: EventType.RoomMessageEncrypted,
+            batch: [],
+        };
+
+        try {
+            await Promise.all(userDeviceInfoArr.map(async ({ userId, deviceInfo }) => {
+                const deviceId = deviceInfo.deviceId;
+                const encryptedContent: IEncryptedContent = {
+                    algorithm: olmlib.OLM_ALGORITHM,
+                    sender_key: this.olmDevice.deviceCurve25519Key,
+                    ciphertext: {},
+                };
+
+                toDeviceBatch.batch.push({
+                    userId,
+                    deviceId,
+                    payload: encryptedContent,
+                });
+
+                await olmlib.ensureOlmSessionsForDevices(
+                    this.olmDevice,
+                    this.baseApis,
+                    { [userId]: [deviceInfo] },
+                );
+                await olmlib.encryptMessageForDevice(
+                    encryptedContent.ciphertext,
+                    this.userId,
+                    this.deviceId,
+                    this.olmDevice,
+                    userId,
+                    deviceInfo,
+                    payload,
+                );
+            }));
+
+            // prune out any devices that encryptMessageForDevice could not encrypt for,
+            // in which case it will have just not added anything to the ciphertext object.
+            // There's no point sending messages to devices if we couldn't encrypt to them,
+            // since that's effectively a blank message.
+            toDeviceBatch.batch = toDeviceBatch.batch.filter(msg => {
+                if (Object.keys(msg.payload.ciphertext).length > 0) {
+                    return true;
+                } else {
+                    logger.log(`No ciphertext for device ${msg.userId}:${msg.deviceId}: pruning`);
+                    return false;
+                }
+            });
+
+            try {
+                await this.baseApis.queueToDevice(toDeviceBatch);
+            } catch (e) {
+                logger.error("sendToDevice failed", e);
+                throw e;
+            }
+        } catch (e) {
+            logger.error("encryptAndSendToDevices promises failed", e);
+            throw e;
+        }
+    }
+
    private onMembership = (event: MatrixEvent, member: RoomMember, oldMembership?: string) => {
        try {
            this.onRoomMembership(event, member, oldMembership);
@@ -3119,8 +3208,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
                this.secretStorage.onRequestReceived(event);
            } else if (event.getType() === "m.secret.send") {
                this.secretStorage.onSecretReceived(event);
-            } else if (event.getType() === "m.room_key.withheld"
-                || event.getType() === "org.matrix.room_key.withheld") {
+            } else if (event.getType() === "m.room_key.withheld") {
                this.onRoomKeyWithheldEvent(event);
            } else if (event.getContent().transaction_id) {
                this.onKeyVerificationMessage(event);
@@ -3445,7 +3533,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap

        const roomId = member.roomId;

-        const alg = this.roomEncryptors[roomId];
+        const alg = this.roomEncryptors.get(roomId);
        if (!alg) {
            // not encrypting in this room
            return;
@@ -3546,11 +3634,11 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
            ` for ${roomId} / ${body.session_id} (id ${req.requestId})`);

        if (userId !== this.userId) {
-            if (!this.roomEncryptors[roomId]) {
+            if (!this.roomEncryptors.get(roomId)) {
                logger.debug(`room key request for unencrypted room ${roomId}`);
                return;
            }
-            const encryptor = this.roomEncryptors[roomId];
+            const encryptor = this.roomEncryptors.get(roomId);
            const device = this.deviceList.getStoredDevice(userId, deviceId);
            if (!device) {
                logger.debug(`Ignoring keyshare for unknown device ${userId}:${deviceId}`);
@@ -3586,12 +3674,12 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap

        // if we don't have a decryptor for this room/alg, we don't have
        // the keys for the requested events, and can drop the requests.
-        if (!this.roomDecryptors[roomId]) {
+        if (!this.roomDecryptors.has(roomId)) {
            logger.log(`room key request for unencrypted room ${roomId}`);
            return;
        }

-        const decryptor = this.roomDecryptors[roomId][alg];
+        const decryptor = this.roomDecryptors.get(roomId).get(alg);
        if (!decryptor) {
            logger.log(`room key request for unknown alg ${alg} in room ${roomId}`);
            return;
@@ -3657,23 +3745,24 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     * unknown
     */
    public getRoomDecryptor(roomId: string, algorithm: string): DecryptionAlgorithm {
-        let decryptors: Record<string, DecryptionAlgorithm>;
+        let decryptors: Map<string, DecryptionAlgorithm>;
        let alg: DecryptionAlgorithm;

        roomId = roomId || null;
        if (roomId) {
-            decryptors = this.roomDecryptors[roomId];
+            decryptors = this.roomDecryptors.get(roomId);
            if (!decryptors) {
-                this.roomDecryptors[roomId] = decryptors = {};
+                decryptors = new Map<string, DecryptionAlgorithm>();
+                this.roomDecryptors.set(roomId, decryptors);
            }

-            alg = decryptors[algorithm];
+            alg = decryptors.get(algorithm);
            if (alg) {
                return alg;
            }
        }

-        const AlgClass = algorithms.DECRYPTION_CLASSES[algorithm];
+        const AlgClass = algorithms.DECRYPTION_CLASSES.get(algorithm);
        if (!AlgClass) {
            throw new algorithms.DecryptionError(
                'UNKNOWN_ENCRYPTION_ALGORITHM',
@@ -3689,7 +3778,7 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
        });

        if (decryptors) {
-            decryptors[algorithm] = alg;
+            decryptors.set(algorithm, alg);
        }
        return alg;
    }
@@ -3703,9 +3792,9 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     */
    private getRoomDecryptors(algorithm: string): DecryptionAlgorithm[] {
        const decryptors = [];
-        for (const d of Object.values(this.roomDecryptors)) {
-            if (algorithm in d) {
-                decryptors.push(d[algorithm]);
+        for (const d of this.roomDecryptors.values()) {
+            if (d.has(algorithm)) {
+                decryptors.push(d.get(algorithm));
            }
        }
        return decryptors;
@@ -26,7 +26,7 @@ import {
    Mode,
    OutgoingRoomKeyRequest,
 } from "./base";
-import { IRoomKeyRequestBody } from "../index";
+import { IRoomKeyRequestBody, IRoomKeyRequestRecipient } from "../index";
 import { ICrossSigningKey } from "../../client";
 import { IOlmDevice } from "../algorithms/megolm";
 import { IRoomEncryption } from "../RoomList";
@@ -261,7 +261,9 @@ export class Backend implements CryptoStore {
            const cursor = this.result;
            if (cursor) {
                const keyReq = cursor.value;
-                if (keyReq.recipients.includes({ userId, deviceId })) {
+                if (keyReq.recipients.some((recipient: IRoomKeyRequestRecipient) =>
+                    recipient.userId === userId && recipient.deviceId === deviceId,
+                )) {
                    results.push(keyReq);
                }
                cursor.continue();
@@ -191,11 +191,13 @@ export class MemoryCryptoStore implements CryptoStore {
        deviceId: string,
        wantedStates: number[],
    ): Promise<OutgoingRoomKeyRequest[]> {
-        const results = [];
+        const results: OutgoingRoomKeyRequest[] = [];

        for (const req of this.outgoingRoomKeyRequests) {
            for (const state of wantedStates) {
-                if (req.state === state && req.recipients.includes({ userId, deviceId })) {
+                if (req.state === state && req.recipients.some(
+                    (recipient) => recipient.userId === userId && recipient.deviceId === deviceId,
+                )) {
                    results.push(req);
                }
            }
@@ -180,6 +180,7 @@ function generateSas(sasBytes: number[], methods: string[]): IGeneratedSas {

 const macMethods = {
    "hkdf-hmac-sha256": "calculate_mac",
+    "org.matrix.msc3783.hkdf-hmac-sha256": "calculate_mac_fixed_base64",
    "hmac-sha256": "calculate_mac_long_kdf",
 };

@@ -221,7 +222,7 @@ const calculateKeyAgreement = {
 */
 const KEY_AGREEMENT_LIST = ["curve25519-hkdf-sha256", "curve25519"];
 const HASHES_LIST = ["sha256"];
-const MAC_LIST = ["hkdf-hmac-sha256", "hmac-sha256"];
+const MAC_LIST = ["org.matrix.msc3783.hkdf-hmac-sha256", "hkdf-hmac-sha256", "hmac-sha256"];
 const SAS_LIST = Object.keys(sasGenerators);

 const KEY_AGREEMENT_SET = new Set(KEY_AGREEMENT_LIST);
@@ -111,6 +111,7 @@ interface IRequest extends _Request {

 interface IRequestOpts<T> {
    prefix?: string;
+    baseUrl?: string;
    localTimeoutMs?: number;
    headers?: Record<string, string>;
    json?: boolean; // defaults to true
@@ -576,6 +577,9 @@ export class MatrixHttpApi {
     * @param {string=} opts.prefix The full prefix to use e.g.
     * "/_matrix/client/v2_alpha". If not specified, uses this.opts.prefix.
     *
+     * @param {string=} opts.baseUrl The alternative base url to use.
+     * If not specified, uses this.opts.baseUrl
+     *
     * @param {Object=} opts.headers map of additional request headers
     *
     * @return {Promise} Resolves to <code>{data: {Object},
@@ -671,7 +675,8 @@ export class MatrixHttpApi {
        opts?: O,
    ): IAbortablePromise<ResponseType<T, O>> {
        const prefix = opts?.prefix ?? this.opts.prefix;
-        const fullUri = this.opts.baseUrl + prefix + path;
+        const baseUrl = opts?.baseUrl ?? this.opts.baseUrl;
+        const fullUri = baseUrl + prefix + path;

        return this.requestOtherUrl<T, O>(callback, method, fullUri, queryParams, data, opts);
    }
@@ -250,12 +250,9 @@ export class InteractiveAuth {
        if (!this.data?.flows) {
            this.busyChangedCallback?.(true);
            // use the existing sessionId, if one is present.
-            let auth = null;
-            if (this.data.session) {
-                auth = {
-                    session: this.data.session,
-                };
-            }
+            const auth = this.data.session
+                ? { session: this.data.session }
+                : null;
            this.doRequest(auth).finally(() => {
                this.busyChangedCallback?.(false);
            });
@@ -312,7 +309,7 @@ export class InteractiveAuth {
     * @return {string} session id
     */
    public getSessionId(): string {
-        return this.data ? this.data.session : undefined;
+        return this.data?.session;
    }

    /**
@@ -477,6 +474,9 @@ export class InteractiveAuth {
                    logger.log("Background poll request failed doing UI auth: ignoring", error);
                }
            }
+            if (!error.data) {
+                error.data = {};
+            }
            // if the error didn't come with flows, completed flows or session ID,
            // copy over the ones we have. Synapse sometimes sends responses without
            // any UI auth data (eg. when polling for email validation, if the email
@@ -539,19 +539,17 @@ export class InteractiveAuth {
            return;
        }

-        if (this.data && this.data.errcode || this.data.error) {
+        if (this.data?.errcode || this.data?.error) {
            this.stateUpdatedCallback(nextStage, {
-                errcode: this.data.errcode || "",
-                error: this.data.error || "",
+                errcode: this.data?.errcode || "",
+                error: this.data?.error || "",
            });
            return;
        }

-        const stageStatus: IStageStatus = {};
-        if (nextStage == EMAIL_STAGE_TYPE) {
-            stageStatus.emailSid = this.emailSid;
-        }
-        this.stateUpdatedCallback(nextStage, stageStatus);
+        this.stateUpdatedCallback(nextStage, nextStage === EMAIL_STAGE_TYPE
+            ? { emailSid: this.emailSid }
+            : {});
    }

    /**
@@ -0,0 +1,38 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export type ToDevicePayload = Record<string, any>;
+
+export interface ToDeviceMessage {
+    userId: string;
+    deviceId: string;
+    payload: ToDevicePayload;
+}
+
+export interface ToDeviceBatch {
+    eventType: string;
+    batch: ToDeviceMessage[];
+}
+
+// Only used internally
+export interface ToDeviceBatchWithTxnId extends ToDeviceBatch {
+    txnId: string;
+}
+
+// Only used internally
+export interface IndexedToDeviceBatch extends ToDeviceBatchWithTxnId {
+    id: number;
+}
@@ -197,7 +197,7 @@ export class Beacon extends TypedEventEmitter<Exclude<BeaconEvent, BeaconEvent.N
        const startTimestamp = this._beaconInfo?.timestamp > Date.now() ?
            this._beaconInfo?.timestamp - 360000 /* 6min */ :
            this._beaconInfo?.timestamp;
-        this._isLive = this._beaconInfo?.live &&
+        this._isLive = !!this._beaconInfo?.live &&
            isTimestampInDuration(startTimestamp, this._beaconInfo?.timeout, Date.now());

        if (prevLiveness !== this.isLive) {
@@ -86,7 +86,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
    private readonly displayPendingEvents: boolean;
    private liveTimeline: EventTimeline;
    private timelines: EventTimeline[];
-    private _eventIdToTimeline: Record<string, EventTimeline>;
+    private _eventIdToTimeline = new Map<string, EventTimeline>();
    private filter?: Filter;

    /**
@@ -138,7 +138,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime

        // just a list - *not* ordered.
        this.timelines = [this.liveTimeline];
-        this._eventIdToTimeline = {};
+        this._eventIdToTimeline = new Map<string, EventTimeline>();

        this.filter = opts.filter;

@@ -210,7 +210,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
     * @return {module:models/event-timeline~EventTimeline} timeline
     */
    public eventIdToTimeline(eventId: string): EventTimeline {
-        return this._eventIdToTimeline[eventId];
+        return this._eventIdToTimeline.get(eventId);
    }

    /**
@@ -220,10 +220,10 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
     * @param {String} newEventId  event ID of the replacement event
     */
    public replaceEventId(oldEventId: string, newEventId: string): void {
-        const existingTimeline = this._eventIdToTimeline[oldEventId];
+        const existingTimeline = this._eventIdToTimeline.get(oldEventId);
        if (existingTimeline) {
-            delete this._eventIdToTimeline[oldEventId];
-            this._eventIdToTimeline[newEventId] = existingTimeline;
+            this._eventIdToTimeline.delete(oldEventId);
+            this._eventIdToTimeline.set(newEventId, existingTimeline);
        }
    }

@@ -257,7 +257,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime

        if (resetAllTimelines) {
            this.timelines = [newTimeline];
-            this._eventIdToTimeline = {};
+            this._eventIdToTimeline = new Map<string, EventTimeline>();
        } else {
            this.timelines.push(newTimeline);
        }
@@ -288,7 +288,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
     * the given event, or null if unknown
     */
    public getTimelineForEvent(eventId: string): EventTimeline | null {
-        const res = this._eventIdToTimeline[eventId];
+        const res = this._eventIdToTimeline.get(eventId);
        return (res === undefined) ? null : res;
    }

@@ -450,7 +450,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
            const event = events[i];
            const eventId = event.getId();

-            const existingTimeline = this._eventIdToTimeline[eventId];
+            const existingTimeline = this._eventIdToTimeline.get(eventId);

            if (!existingTimeline) {
                // we don't know about this event yet. Just add it to the timeline.
@@ -601,7 +601,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
            }
        }

-        const timeline = this._eventIdToTimeline[event.getId()];
+        const timeline = this._eventIdToTimeline.get(event.getId());
        if (timeline) {
            if (duplicateStrategy === DuplicateStrategy.Replace) {
                debuglog("EventTimelineSet.addLiveEvent: replacing duplicate event " + event.getId());
@@ -697,7 +697,7 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
            roomState,
            timelineWasEmpty,
        });
-        this._eventIdToTimeline[eventId] = timeline;
+        this._eventIdToTimeline.set(eventId, timeline);

        this.relations.aggregateParentEvent(event);
        this.relations.aggregateChildEvent(event, this);
@@ -725,10 +725,10 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
        newEventId: string,
    ): void {
        // XXX: why don't we infer newEventId from localEvent?
-        const existingTimeline = this._eventIdToTimeline[oldEventId];
+        const existingTimeline = this._eventIdToTimeline.get(oldEventId);
        if (existingTimeline) {
-            delete this._eventIdToTimeline[oldEventId];
-            this._eventIdToTimeline[newEventId] = existingTimeline;
+            this._eventIdToTimeline.delete(oldEventId);
+            this._eventIdToTimeline.set(newEventId, existingTimeline);
        } else {
            if (this.filter) {
                if (this.filter.filterRoomTimeline([localEvent]).length) {
@@ -753,14 +753,14 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
     * in this room.
     */
    public removeEvent(eventId: string): MatrixEvent | null {
-        const timeline = this._eventIdToTimeline[eventId];
+        const timeline = this._eventIdToTimeline.get(eventId);
        if (!timeline) {
            return null;
        }

        const removed = timeline.removeEvent(eventId);
        if (removed) {
-            delete this._eventIdToTimeline[eventId];
+            this._eventIdToTimeline.delete(eventId);
            const data = {
                timeline: timeline,
            };
@@ -787,8 +787,8 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
            return 0;
        }

-        const timeline1 = this._eventIdToTimeline[eventId1];
-        const timeline2 = this._eventIdToTimeline[eventId2];
+        const timeline1 = this._eventIdToTimeline.get(eventId1);
+        const timeline2 = this._eventIdToTimeline.get(eventId2);

        if (timeline1 === undefined) {
            return null;
@@ -26,7 +26,7 @@ import { logger } from '../logger';
 import { VerificationRequest } from "../crypto/verification/request/VerificationRequest";
 import { EVENT_VISIBILITY_CHANGE_TYPE, EventType, MsgType, RelationType } from "../@types/event";
 import { Crypto, IEventDecryptionResult } from "../crypto";
-import { deepSortedObjectEntries } from "../utils";
+import { deepSortedObjectEntries, internaliseString } from "../utils";
 import { RoomMember } from "./room-member";
 import { Thread, ThreadEvent, EventHandlerMap as ThreadEventHandlerMap, THREAD_RELATION_TYPE } from "./thread";
 import { IActionsObject } from '../pushprocessor';
@@ -37,14 +37,6 @@ import { EventStatus } from "./event-status";

 export { EventStatus } from "./event-status";

-const interns: Record<string, string> = {};
-function intern(str: string): string {
-    if (!interns[str]) {
-        interns[str] = str;
-    }
-    return interns[str];
-}
-
 /* eslint-disable camelcase */
 export interface IContent {
    [key: string]: any;
@@ -326,17 +318,17 @@ export class MatrixEvent extends TypedEventEmitter<EmittedEvents, MatrixEventHan
        // of space if we don't intern it.
        ["state_key", "type", "sender", "room_id", "membership"].forEach((prop) => {
            if (typeof event[prop] !== "string") return;
-            event[prop] = intern(event[prop]);
+            event[prop] = internaliseString(event[prop]);
        });

        ["membership", "avatar_url", "displayname"].forEach((prop) => {
            if (typeof event.content?.[prop] !== "string") return;
-            event.content[prop] = intern(event.content[prop]);
+            event.content[prop] = internaliseString(event.content[prop]);
        });

        ["rel_type"].forEach((prop) => {
            if (typeof event.content?.["m.relates_to"]?.[prop] !== "string") return;
-            event.content["m.relates_to"][prop] = intern(event.content["m.relates_to"][prop]);
+            event.content["m.relates_to"][prop] = internaliseString(event.content["m.relates_to"][prop]);
        });

        this.txnId = event.txn_id || null;
@@ -796,6 +788,8 @@ export class MatrixEvent extends TypedEventEmitter<EmittedEvents, MatrixEventHan
                    // not a decryption error: log the whole exception as an error
                    // (and don't bother with a retry)
                    const re = options.isRetry ? 're' : '';
+                    // For find results: this can produce "Error decrypting event (id=$ev)" and
+                    // "Error redecrypting event (id=$ev)".
                    logger.error(
                        `Error ${re}decrypting event ` +
                        `(id=${this.getId()}): ${e.stack || e}`,
@@ -23,14 +23,8 @@ import { Room } from "./room";

 export class RelationsContainer {
    // A tree of objects to access a set of related children for an event, as in:
-    // this.relations[parentEventId][relationType][relationEventType]
-    private relations: {
-        [parentEventId: string]: {
-            [relationType: RelationType | string]: {
-                [eventType: EventType | string]: Relations;
-            };
-        };
-    } = {};
+    // this.relations.get(parentEventId).get(relationType).get(relationEventType)
+    private relations = new Map<string, Map<RelationType | string, Map<EventType | string, Relations>>>();

    constructor(private readonly client: MatrixClient, private readonly room?: Room) {
    }
@@ -57,14 +51,15 @@ export class RelationsContainer {
        relationType: RelationType | string,
        eventType: EventType | string,
    ): Relations | undefined {
-        return this.relations[eventId]?.[relationType]?.[eventType];
+        return this.relations.get(eventId)?.get(relationType)?.get(eventType);
    }

    public getAllChildEventsForEvent(parentEventId: string): MatrixEvent[] {
-        const relationsForEvent = this.relations[parentEventId] ?? {};
+        const relationsForEvent = this.relations.get(parentEventId)
+            ?? new Map<RelationType | string, Map<EventType | string, Relations>>();
        const events: MatrixEvent[] = [];
-        for (const relationsRecord of Object.values(relationsForEvent)) {
-            for (const relations of Object.values(relationsRecord)) {
+        for (const relationsRecord of relationsForEvent.values()) {
+            for (const relations of relationsRecord.values()) {
                events.push(...relations.getRelations());
            }
        }
@@ -79,11 +74,11 @@ export class RelationsContainer {
     * @param {MatrixEvent} event The event to check as relation target.
     */
    public aggregateParentEvent(event: MatrixEvent): void {
-        const relationsForEvent = this.relations[event.getId()];
+        const relationsForEvent = this.relations.get(event.getId());
        if (!relationsForEvent) return;

-        for (const relationsWithRelType of Object.values(relationsForEvent)) {
-            for (const relationsWithEventType of Object.values(relationsWithRelType)) {
+        for (const relationsWithRelType of relationsForEvent.values()) {
+            for (const relationsWithEventType of relationsWithRelType.values()) {
                relationsWithEventType.setTargetEvent(event);
            }
        }
@@ -123,23 +118,26 @@ export class RelationsContainer {
        const { event_id: relatesToEventId, rel_type: relationType } = relation;
        const eventType = event.getType();

-        let relationsForEvent = this.relations[relatesToEventId];
+        let relationsForEvent = this.relations.get(relatesToEventId);
        if (!relationsForEvent) {
-            relationsForEvent = this.relations[relatesToEventId] = {};
+            relationsForEvent = new Map<RelationType | string, Map<EventType | string, Relations>>();
+            this.relations.set(relatesToEventId, relationsForEvent);
        }

-        let relationsWithRelType = relationsForEvent[relationType];
+        let relationsWithRelType = relationsForEvent.get(relationType);
        if (!relationsWithRelType) {
-            relationsWithRelType = relationsForEvent[relationType] = {};
+            relationsWithRelType = new Map<EventType | string, Relations>();
+            relationsForEvent.set(relationType, relationsWithRelType);
        }

-        let relationsWithEventType = relationsWithRelType[eventType];
+        let relationsWithEventType = relationsWithRelType.get(eventType);
        if (!relationsWithEventType) {
-            relationsWithEventType = relationsWithRelType[eventType] = new Relations(
+            relationsWithEventType = new Relations(
                relationType,
                eventType,
                this.client,
            );
+            relationsWithRelType.set(eventType, relationsWithEventType);

            const room = this.room ?? timelineSet?.room;
            const relatesToEvent = timelineSet?.findEventById(relatesToEventId)
@@ -79,7 +79,7 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>
    public readonly reEmitter = new TypedReEmitter<EmittedEvents, EventHandlerMap>(this);
    private sentinels: Record<string, RoomMember> = {}; // userId: RoomMember
    // stores fuzzy matches to a list of userIDs (applies utils.removeHiddenChars to keys)
-    private displayNameToUserIds: Record<string, string[]> = {};
+    private displayNameToUserIds = new Map<string, string[]>();
    private userIdsToDisplayNames: Record<string, string> = {};
    private tokenToInvite: Record<string, MatrixEvent> = {}; // 3pid invite state_key to m.room.member invite
    private joinedMemberCount: number = null; // cache of the number of joined members
@@ -370,7 +370,6 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>
        });

        this.onBeaconLivenessChange();
-
        // update higher level data structures. This needs to be done AFTER the
        // core event dict as these structures may depend on other state events in
        // the given array (e.g. disambiguating display names in one go to do both
@@ -401,7 +400,6 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>

                const member = this.getOrCreateMember(userId, event);
                member.setMembershipEvent(event, this);
-
                this.updateMember(member);
                this.emit(RoomStateEvent.Members, event, this, member);
            } else if (event.getType() === EventType.RoomPowerLevels) {
@@ -711,7 +709,7 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>
     * @return {string[]} An array of user IDs or an empty array.
     */
    public getUserIdsWithDisplayName(displayName: string): string[] {
-        return this.displayNameToUserIds[utils.removeHiddenChars(displayName)] || [];
+        return this.displayNameToUserIds.get(utils.removeHiddenChars(displayName)) ?? [];
    }

    /**
@@ -943,11 +941,11 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>
            // the lot.
            const strippedOldName = utils.removeHiddenChars(oldName);

-            const existingUserIds = this.displayNameToUserIds[strippedOldName];
+            const existingUserIds = this.displayNameToUserIds.get(strippedOldName);
            if (existingUserIds) {
                // remove this user ID from this array
                const filteredUserIDs = existingUserIds.filter((id) => id !== userId);
-                this.displayNameToUserIds[strippedOldName] = filteredUserIDs;
+                this.displayNameToUserIds.set(strippedOldName, filteredUserIDs);
            }
        }

@@ -956,10 +954,9 @@ export class RoomState extends TypedEventEmitter<EmittedEvents, EventHandlerMap>
        const strippedDisplayname = displayName && utils.removeHiddenChars(displayName);
        // an empty stripped displayname (undefined/'') will be set to MXID in room-member.js
        if (strippedDisplayname) {
-            if (!this.displayNameToUserIds[strippedDisplayname]) {
-                this.displayNameToUserIds[strippedDisplayname] = [];
-            }
-            this.displayNameToUserIds[strippedDisplayname].push(userId);
+            const arr = this.displayNameToUserIds.get(strippedDisplayname) ?? [];
+            arr.push(userId);
+            this.displayNameToUserIds.set(strippedDisplayname, arr);
        }
    }
 }
@@ -1,5 +1,5 @@
 /*
-Copyright 2015 - 2021 The Matrix.org Foundation C.I.C.
+Copyright 2015 - 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -37,7 +37,8 @@ import {
 import { IRoomVersionsCapability, MatrixClient, PendingEventOrdering, RoomVersionStability } from "../client";
 import { GuestAccess, HistoryVisibility, JoinRule, ResizeMethod } from "../@types/partials";
 import { Filter, IFilterDefinition } from "../filter";
-import { RoomState } from "./room-state";
+import { RoomState, RoomStateEvent, RoomStateEventHandlerMap } from "./room-state";
+import { BeaconEvent, BeaconEventHandlerMap } from "./beacon";
 import {
    Thread,
    ThreadEvent,
@@ -72,7 +73,7 @@ function synthesizeReceipt(userId: string, event: MatrixEvent, receiptType: Rece
                },
            },
        },
-        type: "m.receipt",
+        type: EventType.Receipt,
        room_id: event.getRoomId(),
    });
 }
@@ -172,16 +173,19 @@ export enum RoomEvent {
 }

 type EmittedEvents = RoomEvent
+    | RoomStateEvent.Events
+    | RoomStateEvent.Members
+    | RoomStateEvent.NewMember
+    | RoomStateEvent.Update
+    | RoomStateEvent.Marker
    | ThreadEvent.New
    | ThreadEvent.Update
    | ThreadEvent.NewReply
-    | RoomEvent.Timeline
-    | RoomEvent.TimelineReset
-    | RoomEvent.TimelineRefresh
-    | RoomEvent.HistoryImportedWithinTimeline
-    | RoomEvent.OldStateUpdated
-    | RoomEvent.CurrentStateUpdated
-    | MatrixEventEvent.BeforeRedaction;
+    | MatrixEventEvent.BeforeRedaction
+    | BeaconEvent.New
+    | BeaconEvent.Update
+    | BeaconEvent.Destroy
+    | BeaconEvent.LivenessChange;

 export type RoomEventHandlerMap = {
    [RoomEvent.MyMembership]: (room: Room, membership: string, prevMembership?: string) => void;
@@ -205,7 +209,21 @@ export type RoomEventHandlerMap = {
    ) => void;
    [RoomEvent.TimelineRefresh]: (room: Room, eventTimelineSet: EventTimelineSet) => void;
    [ThreadEvent.New]: (thread: Thread, toStartOfTimeline: boolean) => void;
-} & ThreadHandlerMap & MatrixEventHandlerMap;
+} & ThreadHandlerMap
+    & MatrixEventHandlerMap
+    & Pick<
+        RoomStateEventHandlerMap,
+        RoomStateEvent.Events
+            | RoomStateEvent.Members
+            | RoomStateEvent.NewMember
+            | RoomStateEvent.Update
+            | RoomStateEvent.Marker
+            | BeaconEvent.New
+    >
+    & Pick<
+        BeaconEventHandlerMap,
+        BeaconEvent.Update | BeaconEvent.Destroy | BeaconEvent.LivenessChange
+    >;

 export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap> {
    public readonly reEmitter: TypedReEmitter<EmittedEvents, RoomEventHandlerMap>;
@@ -1068,6 +1086,32 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>

        if (previousCurrentState !== this.currentState) {
            this.emit(RoomEvent.CurrentStateUpdated, this, previousCurrentState, this.currentState);
+
+            // Re-emit various events on the current room state
+            // TODO: If currentState really only exists for backwards
+            // compatibility, shouldn't we be doing this some other way?
+            this.reEmitter.stopReEmitting(previousCurrentState, [
+                RoomStateEvent.Events,
+                RoomStateEvent.Members,
+                RoomStateEvent.NewMember,
+                RoomStateEvent.Update,
+                RoomStateEvent.Marker,
+                BeaconEvent.New,
+                BeaconEvent.Update,
+                BeaconEvent.Destroy,
+                BeaconEvent.LivenessChange,
+            ]);
+            this.reEmitter.reEmit(this.currentState, [
+                RoomStateEvent.Events,
+                RoomStateEvent.Members,
+                RoomStateEvent.NewMember,
+                RoomStateEvent.Update,
+                RoomStateEvent.Marker,
+                BeaconEvent.New,
+                BeaconEvent.Update,
+                BeaconEvent.Destroy,
+                BeaconEvent.LivenessChange,
+            ]);
        }
    }

@@ -1917,6 +1961,27 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
        // If any pending visibility change is waiting for this (older) event,
        this.applyPendingVisibilityEvents(event);

+        // Sliding Sync modifications:
+        // The proxy cannot guarantee every sent event will have a transaction_id field, so we need
+        // to check the event ID against the list of pending events if there is no transaction ID
+        // field. Only do this for events sent by us though as it's potentially expensive to loop
+        // the pending events map.
+        const txnId = event.getUnsigned().transaction_id;
+        if (!txnId && event.getSender() === this.myUserId) {
+            // check the txn map for a matching event ID
+            for (const tid in this.txnToEvent) {
+                const localEvent = this.txnToEvent[tid];
+                if (localEvent.getId() === event.getId()) {
+                    logger.debug("processLiveEvent: found sent event without txn ID: ", tid, event.getId());
+                    // update the unsigned field so we can re-use the same codepaths
+                    const unsigned = event.getUnsigned();
+                    unsigned.transaction_id = tid;
+                    event.setUnsigned(unsigned);
+                    break;
+                }
+            }
+        }
+
        if (event.getUnsigned().transaction_id) {
            const existingEvent = this.txnToEvent[event.getUnsigned().transaction_id];
            if (existingEvent) {
@@ -2173,7 +2238,22 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
            const timeline = this.getTimelineForEvent(newEventId);
            if (timeline) {
                // we've already received the event via the event stream.
-                // nothing more to do here.
+                // nothing more to do here, assuming the transaction ID was correctly matched.
+                // Let's check that.
+                const remoteEvent = this.findEventById(newEventId);
+                const remoteTxnId = remoteEvent.getUnsigned().transaction_id;
+                if (!remoteTxnId) {
+                    // This code path is mostly relevant for the Sliding Sync proxy.
+                    // The remote event did not contain a transaction ID, so we did not handle
+                    // the remote echo yet. Handle it now.
+                    const unsigned = remoteEvent.getUnsigned();
+                    unsigned.transaction_id = event.getTxnId();
+                    remoteEvent.setUnsigned(unsigned);
+                    // the remote event is _already_ in the timeline, so we need to remove it so
+                    // we can convert the local event into the final event.
+                    this.removeEvent(remoteEvent.getId());
+                    this.handleRemoteEcho(remoteEvent, event);
+                }
                return;
            }
        }
@@ -2387,9 +2467,9 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
     */
    public addEphemeralEvents(events: MatrixEvent[]): void {
        for (const event of events) {
-            if (event.getType() === 'm.typing') {
+            if (event.getType() === EventType.Typing) {
                this.currentState.setTypingEvent(event);
-            } else if (event.getType() === 'm.receipt') {
+            } else if (event.getType() === EventType.Receipt) {
                this.addReceipt(event);
            } // else ignore - life is too short for us to care about these events
        }
@@ -2478,7 +2558,7 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
     */
    public getUsersReadUpTo(event: MatrixEvent): string[] {
        return this.getReceiptsForEvent(event).filter(function(receipt) {
-            return [ReceiptType.Read, ReceiptType.ReadPrivate].includes(receipt.type);
+            return utils.isSupportedReceiptType(receipt.type);
        }).map(function(receipt) {
            return receipt.userId;
        });
@@ -2512,25 +2592,64 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
     * @return {String} ID of the latest event that the given user has read, or null.
     */
    public getEventReadUpTo(userId: string, ignoreSynthesized = false): string | null {
-        const timelineSet = this.getUnfilteredTimelineSet();
-        const publicReadReceipt = this.getReadReceiptForUserId(userId, ignoreSynthesized, ReceiptType.Read);
-        const privateReadReceipt = this.getReadReceiptForUserId(userId, ignoreSynthesized, ReceiptType.ReadPrivate);
+        // XXX: This is very very ugly and I hope I won't have to ever add a new
+        // receipt type here again. IMHO this should be done by the server in
+        // some more intelligent manner or the client should just use timestamps

-        // If we have both, compare them
-        let comparison: number | undefined;
-        if (publicReadReceipt?.eventId && privateReadReceipt?.eventId) {
-            comparison = timelineSet.compareEventOrdering(publicReadReceipt?.eventId, privateReadReceipt?.eventId);
+        const timelineSet = this.getUnfilteredTimelineSet();
+        const publicReadReceipt = this.getReadReceiptForUserId(
+            userId,
+            ignoreSynthesized,
+            ReceiptType.Read,
+        );
+        const privateReadReceipt = this.getReadReceiptForUserId(
+            userId,
+            ignoreSynthesized,
+            ReceiptType.ReadPrivate,
+        );
+        const unstablePrivateReadReceipt = this.getReadReceiptForUserId(
+            userId,
+            ignoreSynthesized,
+            ReceiptType.UnstableReadPrivate,
+        );
+
+        // If we have all, compare them
+        if (publicReadReceipt?.eventId && privateReadReceipt?.eventId && unstablePrivateReadReceipt?.eventId) {
+            const comparison1 = timelineSet.compareEventOrdering(
+                publicReadReceipt.eventId,
+                privateReadReceipt.eventId,
+            );
+            const comparison2 = timelineSet.compareEventOrdering(
+                publicReadReceipt.eventId,
+                unstablePrivateReadReceipt.eventId,
+            );
+            const comparison3 = timelineSet.compareEventOrdering(
+                privateReadReceipt.eventId,
+                unstablePrivateReadReceipt.eventId,
+            );
+            if (comparison1 && comparison2 && comparison3) {
+                return (comparison1 > 0)
+                    ? ((comparison2 > 0) ? publicReadReceipt.eventId : unstablePrivateReadReceipt.eventId)
+                    : ((comparison3 > 0) ? privateReadReceipt.eventId : unstablePrivateReadReceipt.eventId);
+            }
        }

-        // If we didn't get a comparison try to compare the ts of the receipts
-        if (!comparison) comparison = publicReadReceipt?.data?.ts - privateReadReceipt?.data?.ts;
+        let latest = privateReadReceipt;
+        [unstablePrivateReadReceipt, publicReadReceipt].forEach((receipt) => {
+            if (receipt?.data?.ts > latest?.data?.ts || !latest) {
+                latest = receipt;
+            }
+        });
+        if (latest?.eventId) return latest?.eventId;

-        // The public receipt is more likely to drift out of date so the private
-        // one has precedence
-        if (!comparison) return privateReadReceipt?.eventId ?? publicReadReceipt?.eventId ?? null;
-
-        // If public read receipt is older, return the private one
-        return (comparison < 0) ? privateReadReceipt?.eventId : publicReadReceipt?.eventId;
+        // The more less likely it is for a read receipt to drift out of date
+        // the bigger is its precedence
+        return (
+            privateReadReceipt?.eventId ??
+            unstablePrivateReadReceipt?.eventId ??
+            publicReadReceipt?.eventId ??
+            null
+        );
    }

    /**
@@ -2839,6 +2958,33 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
        return this.getType() === RoomType.ElementVideo;
    }

+    private roomNameGenerator(state: RoomNameState): string {
+        if (this.client.roomNameGenerator) {
+            const name = this.client.roomNameGenerator(this.roomId, state);
+            if (name !== null) {
+                return name;
+            }
+        }
+
+        switch (state.type) {
+            case RoomNameType.Actual:
+                return state.name;
+            case RoomNameType.Generated:
+                switch (state.subtype) {
+                    case "Inviting":
+                        return `Inviting ${memberNamesToRoomName(state.names, state.count)}`;
+                    default:
+                        return memberNamesToRoomName(state.names, state.count);
+                }
+            case RoomNameType.EmptyRoom:
+                if (state.oldName) {
+                    return `Empty room (was ${state.oldName})`;
+                } else {
+                    return "Empty room";
+                }
+        }
+    }
+
    /**
     * This is an internal method. Calculates the name of the room from the current
     * room state.
@@ -2853,14 +2999,20 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
            // check for an alias, if any. for now, assume first alias is the
            // official one.
            const mRoomName = this.currentState.getStateEvents(EventType.RoomName, "");
-            if (mRoomName && mRoomName.getContent() && mRoomName.getContent().name) {
-                return mRoomName.getContent().name;
+            if (mRoomName?.getContent().name) {
+                return this.roomNameGenerator({
+                    type: RoomNameType.Actual,
+                    name: mRoomName.getContent().name,
+                });
            }
        }

        const alias = this.getCanonicalAlias();
        if (alias) {
-            return alias;
+            return this.roomNameGenerator({
+                type: RoomNameType.Actual,
+                name: alias,
+            });
        }

        const joinedMemberCount = this.currentState.getJoinedMemberCount();
@@ -2892,8 +3044,7 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
            });
        } else {
            let otherMembers = this.currentState.getMembers().filter((m) => {
-                return m.userId !== userId &&
-                    (m.membership === "invite" || m.membership === "join");
+                return m.userId !== userId && (m.membership === "invite" || m.membership === "join");
            });
            otherMembers = otherMembers.filter(({ userId }) => {
                // filter service members
@@ -2911,24 +3062,33 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
        }

        if (inviteJoinCount) {
-            return memberNamesToRoomName(otherNames, inviteJoinCount);
+            return this.roomNameGenerator({
+                type: RoomNameType.Generated,
+                names: otherNames,
+                count: inviteJoinCount,
+            });
        }

        const myMembership = this.getMyMembership();
        // if I have created a room and invited people through
        // 3rd party invites
        if (myMembership == 'join') {
-            const thirdPartyInvites =
-                this.currentState.getStateEvents(EventType.RoomThirdPartyInvite);
+            const thirdPartyInvites = this.currentState.getStateEvents(EventType.RoomThirdPartyInvite);

-            if (thirdPartyInvites && thirdPartyInvites.length) {
+            if (thirdPartyInvites?.length) {
                const thirdPartyNames = thirdPartyInvites.map((i) => {
                    return i.getContent().display_name;
                });

-                return `Inviting ${memberNamesToRoomName(thirdPartyNames)}`;
+                return this.roomNameGenerator({
+                    type: RoomNameType.Generated,
+                    subtype: "Inviting",
+                    names: thirdPartyNames,
+                    count: thirdPartyNames.length + 1,
+                });
            }
        }
+
        // let's try to figure out who was here before
        let leftNames = otherNames;
        // if we didn't have heroes, try finding them in the room state
@@ -2939,11 +3099,20 @@ export class Room extends TypedEventEmitter<EmittedEvents, RoomEventHandlerMap>
                    m.membership !== "join";
            }).map((m) => m.name);
        }
+
+        let oldName: string;
        if (leftNames.length) {
-            return `Empty room (was ${memberNamesToRoomName(leftNames)})`;
-        } else {
-            return "Empty room";
+            oldName = this.roomNameGenerator({
+                type: RoomNameType.Generated,
+                names: leftNames,
+                count: leftNames.length + 1,
+            });
        }
+
+        return this.roomNameGenerator({
+            type: RoomNameType.EmptyRoom,
+            oldName,
+        });
    }

    /**
@@ -3128,8 +3297,33 @@ const ALLOWED_TRANSITIONS: Record<EventStatus, EventStatus[]> = {
    [EventStatus.CANCELLED]: [],
 };

-// TODO i18n
-function memberNamesToRoomName(names: string[], count = (names.length + 1)) {
+export enum RoomNameType {
+    EmptyRoom,
+    Generated,
+    Actual,
+}
+
+export interface EmptyRoomNameState {
+    type: RoomNameType.EmptyRoom;
+    oldName?: string;
+}
+
+export interface GeneratedRoomNameState {
+    type: RoomNameType.Generated;
+    subtype?: "Inviting";
+    names: string[];
+    count: number;
+}
+
+export interface ActualRoomNameState {
+    type: RoomNameType.Actual;
+    name: string;
+}
+
+export type RoomNameState = EmptyRoomNameState | GeneratedRoomNameState | ActualRoomNameState;
+
+// Can be overriden by IMatrixClientCreateOpts::memberNamesToRoomNameFn
+function memberNamesToRoomName(names: string[], count: number): string {
    const countWithoutMe = count - 1;
    if (!names.length) {
        return "Empty room";
@@ -362,13 +362,9 @@ export class PushProcessor {
            return false;
        }

-        let regex;
-
-        if (cond.key == 'content.body') {
-            regex = this.createCachedRegex('(^|\\W)', cond.pattern, '(\\W|$)');
-        } else {
-            regex = this.createCachedRegex('^', cond.pattern, '$');
-        }
+        const regex = cond.key === 'content.body'
+            ? this.createCachedRegex('(^|\\W)', cond.pattern, '(\\W|$)')
+            : this.createCachedRegex('^', cond.pattern, '$');

        return !!val.match(regex);
    }
@@ -57,7 +57,7 @@ export class MatrixScheduler<T = ISendEventResponse> {
     * failure was due to a rate limited request, the time specified in the error is
     * waited before being retried.
     * @param {MatrixEvent} event
-     * @param {Number} attempts
+     * @param {Number} attempts Number of attempts that have been made, including the one that just failed (ie. starting at 1)
     * @param {MatrixError} err
     * @return {Number}
     * @see module:scheduler~retryAlgorithm
@@ -0,0 +1,823 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { NotificationCountType, Room, RoomEvent } from "./models/room";
+import { logger } from './logger';
+import * as utils from "./utils";
+import { EventTimeline } from "./models/event-timeline";
+import { ClientEvent, IStoredClientOpts, MatrixClient, PendingEventOrdering } from "./client";
+import { ISyncStateData, SyncState, _createAndReEmitRoom } from "./sync";
+import { MatrixEvent } from "./models/event";
+import { Crypto } from "./crypto";
+import { IMinimalEvent, IRoomEvent, IStateEvent, IStrippedState } from "./sync-accumulator";
+import { MatrixError } from "./http-api";
+import {
+    Extension,
+    ExtensionState,
+    MSC3575RoomData,
+    MSC3575SlidingSyncResponse,
+    SlidingSync,
+    SlidingSyncEvent,
+    SlidingSyncState,
+} from "./sliding-sync";
+import { EventType, IPushRules } from "./matrix";
+import { PushProcessor } from "./pushprocessor";
+
+// Number of consecutive failed syncs that will lead to a syncState of ERROR as opposed
+// to RECONNECTING. This is needed to inform the client of server issues when the
+// keepAlive is successful but the server /sync fails.
+const FAILED_SYNC_ERROR_THRESHOLD = 3;
+
+class ExtensionE2EE implements Extension {
+    constructor(private readonly crypto: Crypto) {}
+
+    public name(): string {
+        return "e2ee";
+    }
+
+    public when(): ExtensionState {
+        return ExtensionState.PreProcess;
+    }
+
+    public onRequest(isInitial: boolean): object {
+        if (!isInitial) {
+            return undefined;
+        }
+        return {
+            enabled: true, // this is sticky so only send it on the initial request
+        };
+    }
+
+    public async onResponse(data: object): Promise<void> {
+        // Handle device list updates
+        if (data["device_lists"]) {
+            await this.crypto.handleDeviceListChanges({
+                oldSyncToken: "yep", // XXX need to do this so the device list changes get processed :(
+            }, data["device_lists"]);
+        }
+
+        // Handle one_time_keys_count
+        if (data["device_one_time_keys_count"]) {
+            const currentCount = data["device_one_time_keys_count"].signed_curve25519 || 0;
+            this.crypto.updateOneTimeKeyCount(currentCount);
+        }
+        if (data["device_unused_fallback_key_types"] ||
+                data["org.matrix.msc2732.device_unused_fallback_key_types"]) {
+            // The presence of device_unused_fallback_key_types indicates that the
+            // server supports fallback keys. If there's no unused
+            // signed_curve25519 fallback key we need a new one.
+            const unusedFallbackKeys = data["device_unused_fallback_key_types"] ||
+                data["org.matrix.msc2732.device_unused_fallback_key_types"];
+            this.crypto.setNeedsNewFallback(
+                unusedFallbackKeys instanceof Array &&
+                !unusedFallbackKeys.includes("signed_curve25519"),
+            );
+        }
+    }
+}
+
+class ExtensionToDevice implements Extension {
+    private nextBatch?: string = null;
+
+    constructor(private readonly client: MatrixClient) {}
+
+    public name(): string {
+        return "to_device";
+    }
+
+    public when(): ExtensionState {
+        return ExtensionState.PreProcess;
+    }
+
+    public onRequest(isInitial: boolean): object {
+        const extReq = {
+            since: this.nextBatch !== null ? this.nextBatch : undefined,
+        };
+        if (isInitial) {
+            extReq["limit"] = 100;
+            extReq["enabled"] = true;
+        }
+        return extReq;
+    }
+
+    public async onResponse(data: object): Promise<void> {
+        const cancelledKeyVerificationTxns = [];
+        data["events"] = data["events"] || [];
+        data["events"]
+            .map(this.client.getEventMapper())
+            .map((toDeviceEvent) => { // map is a cheap inline forEach
+                // We want to flag m.key.verification.start events as cancelled
+                // if there's an accompanying m.key.verification.cancel event, so
+                // we pull out the transaction IDs from the cancellation events
+                // so we can flag the verification events as cancelled in the loop
+                // below.
+                if (toDeviceEvent.getType() === "m.key.verification.cancel") {
+                    const txnId = toDeviceEvent.getContent()['transaction_id'];
+                    if (txnId) {
+                        cancelledKeyVerificationTxns.push(txnId);
+                    }
+                }
+
+                // as mentioned above, .map is a cheap inline forEach, so return
+                // the unmodified event.
+                return toDeviceEvent;
+            })
+            .forEach(
+                (toDeviceEvent) => {
+                    const content = toDeviceEvent.getContent();
+                    if (
+                        toDeviceEvent.getType() == "m.room.message" &&
+                        content.msgtype == "m.bad.encrypted"
+                    ) {
+                        // the mapper already logged a warning.
+                        logger.log(
+                            'Ignoring undecryptable to-device event from ' +
+                            toDeviceEvent.getSender(),
+                        );
+                        return;
+                    }
+
+                    if (toDeviceEvent.getType() === "m.key.verification.start"
+                        || toDeviceEvent.getType() === "m.key.verification.request") {
+                        const txnId = content['transaction_id'];
+                        if (cancelledKeyVerificationTxns.includes(txnId)) {
+                            toDeviceEvent.flagCancelled();
+                        }
+                    }
+
+                    this.client.emit(ClientEvent.ToDeviceEvent, toDeviceEvent);
+                },
+            );
+
+        this.nextBatch = data["next_batch"];
+    }
+}
+
+class ExtensionAccountData implements Extension {
+    constructor(private readonly client: MatrixClient) {}
+
+    public name(): string {
+        return "account_data";
+    }
+
+    public when(): ExtensionState {
+        return ExtensionState.PostProcess;
+    }
+
+    public onRequest(isInitial: boolean): object {
+        if (!isInitial) {
+            return undefined;
+        }
+        return {
+            enabled: true,
+        };
+    }
+
+    public onResponse(data: {global: object[], rooms: Record<string, object[]>}): void {
+        if (data.global && data.global.length > 0) {
+            this.processGlobalAccountData(data.global);
+        }
+
+        for (const roomId in data.rooms) {
+            const accountDataEvents = mapEvents(this.client, roomId, data.rooms[roomId]);
+            const room = this.client.getRoom(roomId);
+            if (!room) {
+                logger.warn("got account data for room but room doesn't exist on client:", roomId);
+                continue;
+            }
+            room.addAccountData(accountDataEvents);
+            accountDataEvents.forEach((e) => {
+                this.client.emit(ClientEvent.Event, e);
+            });
+        }
+    }
+
+    private processGlobalAccountData(globalAccountData: object[]): void {
+        const events = mapEvents(this.client, undefined, globalAccountData);
+        const prevEventsMap = events.reduce((m, c) => {
+            m[c.getId()] = this.client.store.getAccountData(c.getType());
+            return m;
+        }, {});
+        this.client.store.storeAccountDataEvents(events);
+        events.forEach(
+            (accountDataEvent) => {
+                // Honour push rules that come down the sync stream but also
+                // honour push rules that were previously cached. Base rules
+                // will be updated when we receive push rules via getPushRules
+                // (see sync) before syncing over the network.
+                if (accountDataEvent.getType() === EventType.PushRules) {
+                    const rules = accountDataEvent.getContent<IPushRules>();
+                    this.client.pushRules = PushProcessor.rewriteDefaultRules(rules);
+                }
+                const prevEvent = prevEventsMap[accountDataEvent.getId()];
+                this.client.emit(ClientEvent.AccountData, accountDataEvent, prevEvent);
+                return accountDataEvent;
+            },
+        );
+    }
+}
+
+/**
+ * A copy of SyncApi such that it can be used as a drop-in replacement for sync v2. For the actual
+ * sliding sync API, see sliding-sync.ts or the class SlidingSync.
+ */
+export class SlidingSyncSdk {
+    private syncState: SyncState = null;
+    private syncStateData: ISyncStateData;
+    private lastPos: string = null;
+    private failCount = 0;
+    private notifEvents: MatrixEvent[] = []; // accumulator of sync events in the current sync response
+
+    constructor(
+        private readonly slidingSync: SlidingSync,
+        private readonly client: MatrixClient,
+        private readonly opts: Partial<IStoredClientOpts> = {},
+    ) {
+        this.opts.initialSyncLimit = this.opts.initialSyncLimit ?? 8;
+        this.opts.resolveInvitesToProfiles = this.opts.resolveInvitesToProfiles || false;
+        this.opts.pollTimeout = this.opts.pollTimeout || (30 * 1000);
+        this.opts.pendingEventOrdering = this.opts.pendingEventOrdering || PendingEventOrdering.Chronological;
+        this.opts.experimentalThreadSupport = this.opts.experimentalThreadSupport === true;
+
+        if (!opts.canResetEntireTimeline) {
+            opts.canResetEntireTimeline = (_roomId: string) => {
+                return false;
+            };
+        }
+
+        if (client.getNotifTimelineSet()) {
+            client.reEmitter.reEmit(client.getNotifTimelineSet(), [
+                RoomEvent.Timeline,
+                RoomEvent.TimelineReset,
+            ]);
+        }
+
+        this.slidingSync.on(SlidingSyncEvent.Lifecycle, this.onLifecycle.bind(this));
+        this.slidingSync.on(SlidingSyncEvent.RoomData, this.onRoomData.bind(this));
+        const extensions: Extension[] = [
+            new ExtensionToDevice(this.client),
+            new ExtensionAccountData(this.client),
+        ];
+        if (this.opts.crypto) {
+            extensions.push(
+                new ExtensionE2EE(this.opts.crypto),
+            );
+        }
+        extensions.forEach((ext) => {
+            this.slidingSync.registerExtension(ext);
+        });
+    }
+
+    private onRoomData(roomId: string, roomData: MSC3575RoomData): void {
+        let room = this.client.store.getRoom(roomId);
+        if (!room) {
+            if (!roomData.initial) {
+                logger.debug("initial flag not set but no stored room exists for room ", roomId, roomData);
+                return;
+            }
+            room = _createAndReEmitRoom(this.client, roomId, this.opts);
+        }
+        this.processRoomData(this.client, room, roomData);
+    }
+
+    private onLifecycle(state: SlidingSyncState, resp: MSC3575SlidingSyncResponse, err?: Error): void {
+        if (err) {
+            logger.debug("onLifecycle", state, err);
+        }
+        switch (state) {
+            case SlidingSyncState.Complete:
+                this.purgeNotifications();
+                // Element won't stop showing the initial loading spinner unless we fire SyncState.Prepared
+                if (!this.lastPos) {
+                    this.updateSyncState(SyncState.Prepared, {
+                        oldSyncToken: this.lastPos,
+                        nextSyncToken: resp.pos,
+                        catchingUp: false,
+                        fromCache: false,
+                    });
+                }
+                // Conversely, Element won't show the room list unless there is at least 1x SyncState.Syncing
+                // so hence for the very first sync we will fire prepared then immediately syncing.
+                this.updateSyncState(SyncState.Syncing, {
+                    oldSyncToken: this.lastPos,
+                    nextSyncToken: resp.pos,
+                    catchingUp: false,
+                    fromCache: false,
+                });
+                this.lastPos = resp.pos;
+                break;
+            case SlidingSyncState.RequestFinished:
+                if (err) {
+                    this.failCount += 1;
+                    this.updateSyncState(
+                        this.failCount > FAILED_SYNC_ERROR_THRESHOLD ? SyncState.Error : SyncState.Reconnecting,
+                        {
+                            error: new MatrixError(err),
+                        },
+                    );
+                    if (this.shouldAbortSync(new MatrixError(err))) {
+                        return; // shouldAbortSync actually stops syncing too so we don't need to do anything.
+                    }
+                } else {
+                    this.failCount = 0;
+                }
+                break;
+        }
+    }
+
+    /**
+     * Sync rooms the user has left.
+     * @return {Promise} Resolved when they've been added to the store.
+     */
+    public async syncLeftRooms() {
+        return []; // TODO
+    }
+
+    /**
+     * Peek into a room. This will result in the room in question being synced so it
+     * is accessible via getRooms(). Live updates for the room will be provided.
+     * @param {string} roomId The room ID to peek into.
+     * @return {Promise} A promise which resolves once the room has been added to the
+     * store.
+     */
+    public async peek(_roomId: string): Promise<Room> {
+        return null; // TODO
+    }
+
+    /**
+     * Stop polling for updates in the peeked room. NOPs if there is no room being
+     * peeked.
+     */
+    public stopPeeking(): void {
+        // TODO
+    }
+
+    /**
+     * Returns the current state of this sync object
+     * @see module:client~MatrixClient#event:"sync"
+     * @return {?String}
+     */
+    public getSyncState(): SyncState {
+        return this.syncState;
+    }
+
+    /**
+     * Returns the additional data object associated with
+     * the current sync state, or null if there is no
+     * such data.
+     * Sync errors, if available, are put in the 'error' key of
+     * this object.
+     * @return {?Object}
+     */
+    public getSyncStateData(): ISyncStateData {
+        return this.syncStateData;
+    }
+
+    private shouldAbortSync(error: MatrixError): boolean {
+        if (error.errcode === "M_UNKNOWN_TOKEN") {
+            // The logout already happened, we just need to stop.
+            logger.warn("Token no longer valid - assuming logout");
+            this.stop();
+            this.updateSyncState(SyncState.Error, { error });
+            return true;
+        }
+        return false;
+    }
+
+    private async processRoomData(client: MatrixClient, room: Room, roomData: MSC3575RoomData) {
+        roomData = ensureNameEvent(client, room.roomId, roomData);
+        const stateEvents = mapEvents(this.client, room.roomId, roomData.required_state);
+        // Prevent events from being decrypted ahead of time
+        // this helps large account to speed up faster
+        // room::decryptCriticalEvent is in charge of decrypting all the events
+        // required for a client to function properly
+        let timelineEvents = mapEvents(this.client, room.roomId, roomData.timeline, false);
+        const ephemeralEvents = []; // TODO this.mapSyncEventsFormat(joinObj.ephemeral);
+
+        // TODO: handle threaded / beacon events
+
+        if (roomData.initial) {
+            // we should not know about any of these timeline entries if this is a genuinely new room.
+            // If we do, then we've effectively done scrollback (e.g requesting timeline_limit: 1 for
+            // this room, then timeline_limit: 50).
+            const knownEvents = new Set<string>();
+            room.getLiveTimeline().getEvents().forEach((e) => {
+                knownEvents.add(e.getId());
+            });
+            // all unknown events BEFORE a known event must be scrollback e.g:
+            //       D E   <-- what we know
+            // A B C D E F <-- what we just received
+            // means:
+            // A B C       <-- scrollback
+            //       D E   <-- dupes
+            //           F <-- new event
+            // We bucket events based on if we have seen a known event yet.
+            const oldEvents: MatrixEvent[] = [];
+            const newEvents: MatrixEvent[] = [];
+            let seenKnownEvent = false;
+            for (let i = timelineEvents.length-1; i >= 0; i--) {
+                const recvEvent = timelineEvents[i];
+                if (knownEvents.has(recvEvent.getId())) {
+                    seenKnownEvent = true;
+                    continue; // don't include this event, it's a dupe
+                }
+                if (seenKnownEvent) {
+                    // old -> new
+                    oldEvents.push(recvEvent);
+                } else {
+                    // old -> new
+                    newEvents.unshift(recvEvent);
+                }
+            }
+            timelineEvents = newEvents;
+            if (oldEvents.length > 0) {
+                // old events are scrollback, insert them now
+                room.addEventsToTimeline(oldEvents, true, room.getLiveTimeline(), roomData.prev_batch);
+            }
+        }
+
+        const encrypted = this.client.isRoomEncrypted(room.roomId);
+        // we do this first so it's correct when any of the events fire
+        if (roomData.notification_count != null) {
+            room.setUnreadNotificationCount(
+                NotificationCountType.Total,
+                roomData.notification_count,
+            );
+        }
+
+        if (roomData.highlight_count != null) {
+            // We track unread notifications ourselves in encrypted rooms, so don't
+            // bother setting it here. We trust our calculations better than the
+            // server's for this case, and therefore will assume that our non-zero
+            // count is accurate.
+            if (!encrypted
+                || (encrypted && room.getUnreadNotificationCount(NotificationCountType.Highlight) <= 0)) {
+                room.setUnreadNotificationCount(
+                    NotificationCountType.Highlight,
+                    roomData.highlight_count,
+                );
+            }
+        }
+
+        if (roomData.invite_state) {
+            const inviteStateEvents = mapEvents(this.client, room.roomId, roomData.invite_state);
+            this.processRoomEvents(room, inviteStateEvents);
+            if (roomData.initial) {
+                room.recalculate();
+                this.client.store.storeRoom(room);
+                this.client.emit(ClientEvent.Room, room);
+            }
+            inviteStateEvents.forEach((e) => {
+                this.client.emit(ClientEvent.Event, e);
+            });
+            room.updateMyMembership("invite");
+            return;
+        }
+
+        if (roomData.initial) {
+            // set the back-pagination token. Do this *before* adding any
+            // events so that clients can start back-paginating.
+            room.getLiveTimeline().setPaginationToken(
+                roomData.prev_batch, EventTimeline.BACKWARDS);
+        }
+
+        /* TODO
+        else if (roomData.limited) {
+
+            let limited = true;
+
+            // we've got a limited sync, so we *probably* have a gap in the
+            // timeline, so should reset. But we might have been peeking or
+            // paginating and already have some of the events, in which
+            // case we just want to append any subsequent events to the end
+            // of the existing timeline.
+            //
+            // This is particularly important in the case that we already have
+            // *all* of the events in the timeline - in that case, if we reset
+            // the timeline, we'll end up with an entirely empty timeline,
+            // which we'll try to paginate but not get any new events (which
+            // will stop us linking the empty timeline into the chain).
+            //
+            for (let i = timelineEvents.length - 1; i >= 0; i--) {
+                const eventId = timelineEvents[i].getId();
+                if (room.getTimelineForEvent(eventId)) {
+                    logger.debug("Already have event " + eventId + " in limited " +
+                        "sync - not resetting");
+                    limited = false;
+
+                    // we might still be missing some of the events before i;
+                    // we don't want to be adding them to the end of the
+                    // timeline because that would put them out of order.
+                    timelineEvents.splice(0, i);
+
+                    // XXX: there's a problem here if the skipped part of the
+                    // timeline modifies the state set in stateEvents, because
+                    // we'll end up using the state from stateEvents rather
+                    // than the later state from timelineEvents. We probably
+                    // need to wind stateEvents forward over the events we're
+                    // skipping.
+                    break;
+                }
+            }
+
+            if (limited) {
+                room.resetLiveTimeline(
+                    roomData.prev_batch,
+                    null, // TODO this.opts.canResetEntireTimeline(room.roomId) ? null : syncEventData.oldSyncToken,
+                );
+
+                // We have to assume any gap in any timeline is
+                // reason to stop incrementally tracking notifications and
+                // reset the timeline.
+                this.client.resetNotifTimelineSet();
+            }
+        } */
+
+        this.processRoomEvents(room, stateEvents, timelineEvents, false);
+
+        // we deliberately don't add ephemeral events to the timeline
+        room.addEphemeralEvents(ephemeralEvents);
+
+        // local fields must be set before any async calls because call site assumes
+        // synchronous execution prior to emitting SlidingSyncState.Complete
+        room.updateMyMembership("join");
+
+        room.recalculate();
+        if (roomData.initial) {
+            client.store.storeRoom(room);
+            client.emit(ClientEvent.Room, room);
+        }
+
+        // check if any timeline events should bing and add them to the notifEvents array:
+        // we'll purge this once we've fully processed the sync response
+        this.addNotifications(timelineEvents);
+
+        const processRoomEvent = async (e: MatrixEvent) => {
+            client.emit(ClientEvent.Event, e);
+            if (e.isState() && e.getType() == EventType.RoomEncryption && this.opts.crypto) {
+                await this.opts.crypto.onCryptoEvent(e);
+            }
+        };
+
+        await utils.promiseMapSeries(stateEvents, processRoomEvent);
+        await utils.promiseMapSeries(timelineEvents, processRoomEvent);
+        ephemeralEvents.forEach(function(e) {
+            client.emit(ClientEvent.Event, e);
+        });
+
+        // Decrypt only the last message in all rooms to make sure we can generate a preview
+        // And decrypt all events after the recorded read receipt to ensure an accurate
+        // notification count
+        room.decryptCriticalEvents();
+    }
+
+    /**
+     * @param {Room} room
+     * @param {MatrixEvent[]} stateEventList A list of state events. This is the state
+     * at the *START* of the timeline list if it is supplied.
+     * @param {MatrixEvent[]} [timelineEventList] A list of timeline events. Lower index
+     * @param {boolean} fromCache whether the sync response came from cache
+     * is earlier in time. Higher index is later.
+     */
+    private processRoomEvents(
+        room: Room,
+        stateEventList: MatrixEvent[],
+        timelineEventList?: MatrixEvent[],
+        fromCache = false,
+    ): void {
+        timelineEventList = timelineEventList || [];
+        stateEventList = stateEventList || [];
+
+        // If there are no events in the timeline yet, initialise it with
+        // the given state events
+        const liveTimeline = room.getLiveTimeline();
+        const timelineWasEmpty = liveTimeline.getEvents().length == 0;
+        if (timelineWasEmpty) {
+            // Passing these events into initialiseState will freeze them, so we need
+            // to compute and cache the push actions for them now, otherwise sync dies
+            // with an attempt to assign to read only property.
+            // XXX: This is pretty horrible and is assuming all sorts of behaviour from
+            // these functions that it shouldn't be. We should probably either store the
+            // push actions cache elsewhere so we can freeze MatrixEvents, or otherwise
+            // find some solution where MatrixEvents are immutable but allow for a cache
+            // field.
+            for (const ev of stateEventList) {
+                this.client.getPushActionsForEvent(ev);
+            }
+            liveTimeline.initialiseState(stateEventList);
+        }
+
+        // If the timeline wasn't empty, we process the state events here: they're
+        // defined as updates to the state before the start of the timeline, so this
+        // starts to roll the state forward.
+        // XXX: That's what we *should* do, but this can happen if we were previously
+        // peeking in a room, in which case we obviously do *not* want to add the
+        // state events here onto the end of the timeline. Historically, the js-sdk
+        // has just set these new state events on the old and new state. This seems
+        // very wrong because there could be events in the timeline that diverge the
+        // state, in which case this is going to leave things out of sync. However,
+        // for now I think it;s best to behave the same as the code has done previously.
+        if (!timelineWasEmpty) {
+            // XXX: As above, don't do this...
+            //room.addLiveEvents(stateEventList || []);
+            // Do this instead...
+            room.oldState.setStateEvents(stateEventList);
+            room.currentState.setStateEvents(stateEventList);
+        }
+
+        // execute the timeline events. This will continue to diverge the current state
+        // if the timeline has any state events in it.
+        // This also needs to be done before running push rules on the events as they need
+        // to be decorated with sender etc.
+        room.addLiveEvents(timelineEventList, {
+            fromCache: fromCache,
+        });
+
+        room.recalculate();
+
+        // resolve invites now we have set the latest state
+        this.resolveInvites(room);
+    }
+
+    private resolveInvites(room: Room): void {
+        if (!room || !this.opts.resolveInvitesToProfiles) {
+            return;
+        }
+        const client = this.client;
+        // For each invited room member we want to give them a displayname/avatar url
+        // if they have one (the m.room.member invites don't contain this).
+        room.getMembersWithMembership("invite").forEach(function(member) {
+            if (member._requestedProfileInfo) return;
+            member._requestedProfileInfo = true;
+            // try to get a cached copy first.
+            const user = client.getUser(member.userId);
+            let promise;
+            if (user) {
+                promise = Promise.resolve({
+                    avatar_url: user.avatarUrl,
+                    displayname: user.displayName,
+                });
+            } else {
+                promise = client.getProfileInfo(member.userId);
+            }
+            promise.then(function(info) {
+                // slightly naughty by doctoring the invite event but this means all
+                // the code paths remain the same between invite/join display name stuff
+                // which is a worthy trade-off for some minor pollution.
+                const inviteEvent = member.events.member;
+                if (inviteEvent.getContent().membership !== "invite") {
+                    // between resolving and now they have since joined, so don't clobber
+                    return;
+                }
+                inviteEvent.getContent().avatar_url = info.avatar_url;
+                inviteEvent.getContent().displayname = info.displayname;
+                // fire listeners
+                member.setMembershipEvent(inviteEvent, room.currentState);
+            }, function(_err) {
+                // OH WELL.
+            });
+        });
+    }
+
+    public retryImmediately(): boolean {
+        return true;
+    }
+
+    /**
+     * Main entry point. Blocks until stop() is called.
+     */
+    public async sync() {
+        logger.debug("Sliding sync init loop");
+
+        //   1) We need to get push rules so we can check if events should bing as we get
+        //      them from /sync.
+        while (!this.client.isGuest()) {
+            try {
+                logger.debug("Getting push rules...");
+                const result = await this.client.getPushRules();
+                logger.debug("Got push rules");
+                this.client.pushRules = result;
+                break;
+            } catch (err) {
+                logger.error("Getting push rules failed", err);
+                if (this.shouldAbortSync(err)) {
+                    return;
+                }
+            }
+        }
+
+        // start syncing
+        await this.slidingSync.start();
+    }
+
+    /**
+     * Stops the sync object from syncing.
+     */
+    public stop(): void {
+        logger.debug("SyncApi.stop");
+        this.slidingSync.stop();
+    }
+
+    /**
+     * Sets the sync state and emits an event to say so
+     * @param {String} newState The new state string
+     * @param {Object} data Object of additional data to emit in the event
+     */
+    private updateSyncState(newState: SyncState, data?: ISyncStateData): void {
+        const old = this.syncState;
+        this.syncState = newState;
+        this.syncStateData = data;
+        this.client.emit(ClientEvent.Sync, this.syncState, old, data);
+    }
+
+    /**
+     * Takes a list of timelineEvents and adds and adds to notifEvents
+     * as appropriate.
+     * This must be called after the room the events belong to has been stored.
+     *
+     * @param {MatrixEvent[]} [timelineEventList] A list of timeline events. Lower index
+     * is earlier in time. Higher index is later.
+     */
+    private addNotifications(timelineEventList: MatrixEvent[]): void {
+        // gather our notifications into this.notifEvents
+        if (!this.client.getNotifTimelineSet()) {
+            return;
+        }
+        for (const timelineEvent of timelineEventList) {
+            const pushActions = this.client.getPushActionsForEvent(timelineEvent);
+            if (pushActions && pushActions.notify &&
+                pushActions.tweaks && pushActions.tweaks.highlight) {
+                this.notifEvents.push(timelineEvent);
+            }
+        }
+    }
+
+    /**
+     * Purge any events in the notifEvents array. Used after a /sync has been complete.
+     * This should not be called at a per-room scope (e.g in onRoomData) because otherwise the ordering
+     * will be messed up e.g room A gets a bing, room B gets a newer bing, but both in the same /sync
+     * response. If we purge at a per-room scope then we could process room B before room A leading to
+     * room B appearing earlier in the notifications timeline, even though it has the higher origin_server_ts.
+     */
+    private purgeNotifications(): void {
+        this.notifEvents.sort(function(a, b) {
+            return a.getTs() - b.getTs();
+        });
+        this.notifEvents.forEach((event) => {
+            this.client.getNotifTimelineSet().addLiveEvent(event);
+        });
+        this.notifEvents = [];
+    }
+}
+
+function ensureNameEvent(client: MatrixClient, roomId: string, roomData: MSC3575RoomData): MSC3575RoomData {
+    // make sure m.room.name is in required_state if there is a name, replacing anything previously
+    // there if need be. This ensures clients transparently 'calculate' the right room name. Native
+    // sliding sync clients should just read the "name" field.
+    if (!roomData.name) {
+        return roomData;
+    }
+    for (const stateEvent of roomData.required_state) {
+        if (stateEvent.type === EventType.RoomName && stateEvent.state_key === "") {
+            stateEvent.content = {
+                name: roomData.name,
+            };
+            return roomData;
+        }
+    }
+    roomData.required_state.push({
+        event_id: "$fake-sliding-sync-name-event-" + roomId,
+        state_key: "",
+        type: EventType.RoomName,
+        content: {
+            name: roomData.name,
+        },
+        sender: client.getUserId(),
+        origin_server_ts: new Date().getTime(),
+    });
+    return roomData;
+}
+
+// Helper functions which set up JS SDK structs are below and are identical to the sync v2 counterparts,
+// just outside the class.
+
+function mapEvents(client: MatrixClient, roomId: string, events: object[], decrypt = true): MatrixEvent[] {
+    const mapper = client.getEventMapper({ decrypt });
+    return (events as Array<IStrippedState | IRoomEvent | IStateEvent | IMinimalEvent>).map(function(e) {
+        e["room_id"] = roomId;
+        return mapper(e);
+    });
+}
@@ -0,0 +1,872 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { logger } from './logger';
+import { IAbortablePromise } from "./@types/partials";
+import { MatrixClient } from "./client";
+import { IRoomEvent, IStateEvent } from "./sync-accumulator";
+import { TypedEventEmitter } from "./models//typed-event-emitter";
+import { sleep, IDeferred, defer } from "./utils";
+
+// /sync requests allow you to set a timeout= but the request may continue
+// beyond that and wedge forever, so we need to track how long we are willing
+// to keep open the connection. This constant is *ADDED* to the timeout= value
+// to determine the max time we're willing to wait.
+const BUFFER_PERIOD_MS = 10 * 1000;
+
+/**
+ * Represents a subscription to a room or set of rooms. Controls which events are returned.
+ */
+export interface MSC3575RoomSubscription {
+    required_state?: string[][];
+    timeline_limit?: number;
+}
+
+/**
+ * Controls which rooms are returned in a given list.
+ */
+export interface MSC3575Filter {
+    is_dm?: boolean;
+    is_encrypted?: boolean;
+    is_invite?: boolean;
+    is_tombstoned?: boolean;
+    room_name_like?: string;
+    room_types?: string[];
+    not_room_types?: string[];
+    spaces?: string[];
+    tags?: string[];
+    not_tags?: string[];
+}
+
+/**
+ * Represents a list subscription.
+ */
+export interface MSC3575List extends MSC3575RoomSubscription {
+    ranges: number[][];
+    sort?: string[];
+    filters?: MSC3575Filter;
+    slow_get_all_rooms?: boolean;
+}
+
+/**
+ * A complete Sliding Sync request.
+ */
+export interface MSC3575SlidingSyncRequest {
+    // json body params
+    lists?: MSC3575List[];
+    unsubscribe_rooms?: string[];
+    room_subscriptions?: Record<string, MSC3575RoomSubscription>;
+    extensions?: object;
+    txn_id?: string;
+
+    // query params
+    pos?: string;
+    timeout?: number;
+    clientTimeout?: number;
+}
+
+export interface MSC3575RoomData {
+    name: string;
+    required_state: IStateEvent[];
+    timeline: (IRoomEvent | IStateEvent)[];
+    notification_count?: number;
+    highlight_count?: number;
+    invite_state?: IStateEvent[];
+    initial?: boolean;
+    limited?: boolean;
+    is_dm?: boolean;
+    prev_batch?: string;
+}
+
+interface ListResponse {
+    count: number;
+    ops: Operation[];
+}
+
+interface BaseOperation {
+    op: string;
+}
+
+interface DeleteOperation extends BaseOperation {
+    op: "DELETE";
+    index: number;
+}
+
+interface InsertOperation extends BaseOperation {
+    op: "INSERT";
+    index: number;
+    room_id: string;
+}
+
+interface InvalidateOperation extends BaseOperation {
+    op: "INVALIDATE";
+    range: [number, number];
+}
+
+interface SyncOperation extends BaseOperation {
+    op: "SYNC";
+    range: [number, number];
+    room_ids: string[];
+}
+
+type Operation = DeleteOperation | InsertOperation | InvalidateOperation | SyncOperation;
+
+/**
+ * A complete Sliding Sync response
+ */
+export interface MSC3575SlidingSyncResponse {
+    pos: string;
+    txn_id?: string;
+    lists: ListResponse[];
+    rooms: Record<string, MSC3575RoomData>;
+    extensions: object;
+}
+
+export enum SlidingSyncState {
+    /**
+     * Fired by SlidingSyncEvent.Lifecycle event immediately before processing the response.
+     */
+    RequestFinished = "FINISHED",
+    /**
+     * Fired by SlidingSyncEvent.Lifecycle event immediately after all room data listeners have been
+     * invoked, but before list listeners.
+     */
+    Complete = "COMPLETE",
+}
+
+/**
+ * Internal Class. SlidingList represents a single list in sliding sync. The list can have filters,
+ * multiple sliding windows, and maintains the index->room_id mapping.
+ */
+class SlidingList {
+    private list: MSC3575List;
+    private isModified: boolean;
+
+    // returned data
+    public roomIndexToRoomId: Record<number, string>;
+    public joinedCount: number;
+
+    /**
+     * Construct a new sliding list.
+     * @param {MSC3575List} list The range, sort and filter values to use for this list.
+     */
+    constructor(list: MSC3575List) {
+        this.replaceList(list);
+    }
+
+    /**
+     * Mark this list as modified or not. Modified lists will return sticky params with calls to getList.
+     * This is useful for the first time the list is sent, or if the list has changed in some way.
+     * @param modified True to mark this list as modified so all sticky parameters will be re-sent.
+     */
+    public setModified(modified: boolean): void {
+        this.isModified = modified;
+    }
+
+    /**
+     * Update the list range for this list. Does not affect modified status as list ranges are non-sticky.
+     * @param newRanges The new ranges for the list
+     */
+    public updateListRange(newRanges: number[][]): void {
+        this.list.ranges = JSON.parse(JSON.stringify(newRanges));
+    }
+
+    /**
+     * Replace list parameters. All fields will be replaced with the new list parameters.
+     * @param list The new list parameters
+     */
+    public replaceList(list: MSC3575List): void {
+        list.filters = list.filters || {};
+        list.ranges = list.ranges || [];
+        this.list = JSON.parse(JSON.stringify(list));
+        this.isModified = true;
+
+        // reset values as the join count may be very different (if filters changed) including the rooms
+        // (e.g. sort orders or sliding window ranges changed)
+
+        // the constantly changing sliding window ranges. Not an array for performance reasons
+        // E.g. tracking ranges 0-99, 500-599, we don't want to have a 600 element array
+        this.roomIndexToRoomId = {};
+        // the total number of joined rooms according to the server, always >= len(roomIndexToRoomId)
+        this.joinedCount = 0;
+    }
+
+    /**
+     * Return a copy of the list suitable for a request body.
+     * @param {boolean} forceIncludeAllParams True to forcibly include all params even if the list
+     * hasn't been modified. Callers may want to do this if they are modifying the list prior to calling
+     * updateList.
+     */
+    public getList(forceIncludeAllParams: boolean): MSC3575List {
+        let list = {
+            ranges: JSON.parse(JSON.stringify(this.list.ranges)),
+        };
+        if (this.isModified || forceIncludeAllParams) {
+            list = JSON.parse(JSON.stringify(this.list));
+        }
+        return list;
+    }
+
+    /**
+     * Check if a given index is within the list range. This is required even though the /sync API
+     * provides explicit updates with index positions because of the following situation:
+     *   0 1 2 3 4 5 6 7 8   indexes
+     *   a b c       d e f   COMMANDS: SYNC 0 2 a b c; SYNC 6 8 d e f;
+     *   a b c       d _ f   COMMAND: DELETE 7;
+     *   e a b c       d f   COMMAND: INSERT 0 e;
+     *   c=3 is wrong as we are not tracking it, ergo we need to see if `i` is in range else drop it
+     * @param i The index to check
+     * @returns True if the index is within a sliding window
+     */
+    public isIndexInRange(i: number): boolean {
+        for (const r of this.list.ranges) {
+            if (r[0] <= i && i <= r[1]) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
+/**
+ * When onResponse extensions should be invoked: before or after processing the main response.
+ */
+export enum ExtensionState {
+    // Call onResponse before processing the response body. This is useful when your extension is
+    // preparing the ground for the response body e.g. processing to-device messages before the
+    // encrypted event arrives.
+    PreProcess = "ExtState.PreProcess",
+    // Call onResponse after processing the response body. This is useful when your extension is
+    // decorating data from the client, and you rely on MatrixClient.getRoom returning the Room object
+    // e.g. room account data.
+    PostProcess = "ExtState.PostProcess",
+}
+
+/**
+ * An interface that must be satisfied to register extensions
+ */
+export interface Extension {
+    /**
+     * The extension name to go under 'extensions' in the request body.
+     * @returns The JSON key.
+     */
+    name(): string;
+    /**
+     * A function which is called when the request JSON is being formed.
+     * Returns the data to insert under this key.
+     * @param isInitial True when this is part of the initial request (send sticky params)
+     * @returns The request JSON to send.
+     */
+    onRequest(isInitial: boolean): object;
+    /**
+     * A function which is called when there is response JSON under this extension.
+     * @param data The response JSON under the extension name.
+     */
+    onResponse(data: object);
+    /**
+     * Controls when onResponse should be called.
+     * @returns The state when it should be called.
+     */
+    when(): ExtensionState;
+}
+
+/**
+ * Events which can be fired by the SlidingSync class. These are designed to provide different levels
+ * of information when processing sync responses.
+ *  - RoomData: concerns rooms, useful for SlidingSyncSdk to update its knowledge of rooms.
+ *  - Lifecycle: concerns callbacks at various well-defined points in the sync process.
+ *  - List: concerns lists, useful for UI layers to re-render room lists.
+ * Specifically, the order of event invocation is:
+ *  - Lifecycle (state=RequestFinished)
+ *  - RoomData (N times)
+ *  - Lifecycle (state=Complete)
+ *  - List (at most once per list)
+ */
+export enum SlidingSyncEvent {
+    /**
+     * This event fires when there are updates for a room. Fired as and when rooms are encountered
+     * in the response.
+     */
+    RoomData = "SlidingSync.RoomData",
+    /**
+     * This event fires at various points in the /sync loop lifecycle.
+     *  - SlidingSyncState.RequestFinished: Fires after we receive a valid response but before the
+     * response has been processed. Perform any pre-process steps here. If there was a problem syncing,
+     * `err` will be set (e.g network errors).
+     *  - SlidingSyncState.Complete: Fires after all SlidingSyncEvent.RoomData have been fired but before
+     * SlidingSyncEvent.List.
+     */
+    Lifecycle = "SlidingSync.Lifecycle",
+    /**
+     * This event fires whenever there has been a change to this list index. It fires exactly once
+     * per list, even if there were multiple operations for the list.
+     * It fires AFTER Lifecycle and RoomData events.
+     */
+    List = "SlidingSync.List",
+}
+
+export type SlidingSyncEventHandlerMap = {
+    [SlidingSyncEvent.RoomData]: (roomId: string, roomData: MSC3575RoomData) => void;
+    [SlidingSyncEvent.Lifecycle]: (state: SlidingSyncState, resp: MSC3575SlidingSyncResponse, err: Error) => void;
+    [SlidingSyncEvent.List]: (
+        listIndex: number, joinedCount: number, roomIndexToRoomId: Record<number, string>,
+    ) => void;
+};
+
+/**
+ * SlidingSync is a high-level data structure which controls the majority of sliding sync.
+ * It has no hooks into JS SDK except for needing a MatrixClient to perform the HTTP request.
+ * This means this class (and everything it uses) can be used in isolation from JS SDK if needed.
+ * To hook this up with the JS SDK, you need to use SlidingSyncSdk.
+ */
+export class SlidingSync extends TypedEventEmitter<SlidingSyncEvent, SlidingSyncEventHandlerMap> {
+    private lists: SlidingList[];
+    private listModifiedCount = 0;
+    private terminated = false;
+    // flag set when resend() is called because we cannot rely on detecting AbortError in JS SDK :(
+    private needsResend = false;
+    // the txn_id to send with the next request.
+    private txnId?: string = null;
+    // a list (in chronological order of when they were sent) of objects containing the txn ID and
+    // a defer to resolve/reject depending on whether they were successfully sent or not.
+    private txnIdDefers: (IDeferred<string> & { txnId: string})[] = [];
+    // map of extension name to req/resp handler
+    private extensions: Record<string, Extension> = {};
+
+    private desiredRoomSubscriptions = new Set<string>(); // the *desired* room subscriptions
+    private confirmedRoomSubscriptions = new Set<string>();
+
+    private pendingReq?: IAbortablePromise<MSC3575SlidingSyncResponse>;
+
+    /**
+     * Create a new sliding sync instance
+     * @param {string} proxyBaseUrl The base URL of the sliding sync proxy
+     * @param {MSC3575List[]} lists The lists to use for sliding sync.
+     * @param {MSC3575RoomSubscription} roomSubscriptionInfo The params to use for room subscriptions.
+     * @param {MatrixClient} client The client to use for /sync calls.
+     * @param {number} timeoutMS The number of milliseconds to wait for a response.
+     */
+    constructor(
+        private readonly proxyBaseUrl: string,
+        lists: MSC3575List[],
+        private roomSubscriptionInfo: MSC3575RoomSubscription,
+        private readonly client: MatrixClient,
+        private readonly timeoutMS: number,
+    ) {
+        super();
+        this.lists = lists.map((l) => new SlidingList(l));
+    }
+
+    /**
+     * Get the length of the sliding lists.
+     * @returns The number of lists in the sync request
+     */
+    public listLength(): number {
+        return this.lists.length;
+    }
+
+    /**
+     * Get the room data for a list.
+     * @param index The list index
+     * @returns The list data which contains the rooms in this list
+     */
+    public getListData(index: number): {joinedCount: number, roomIndexToRoomId: Record<number, string>} {
+        if (!this.lists[index]) {
+            return null;
+        }
+        return {
+            joinedCount: this.lists[index].joinedCount,
+            roomIndexToRoomId: Object.assign({}, this.lists[index].roomIndexToRoomId),
+        };
+    }
+
+    /**
+     * Get the full list parameters for a list index. This function is provided for callers to use
+     * in conjunction with setList to update fields on an existing list.
+     * @param index The list index to get the list for.
+     * @returns A copy of the list or undefined.
+     */
+    public getList(index: number): MSC3575List {
+        if (!this.lists[index]) {
+            return null;
+        }
+        return this.lists[index].getList(true);
+    }
+
+    /**
+     * Set new ranges for an existing list. Calling this function when _only_ the ranges have changed
+     * is more efficient than calling setList(index,list) as this function won't resend sticky params,
+     * whereas setList always will.
+     * @param index The list index to modify
+     * @param ranges The new ranges to apply.
+     * @return A promise which resolves to the transaction ID when it has been received down sync
+     * (or rejects with the transaction ID if the action was not applied e.g the request was cancelled
+     * immediately after sending, in which case the action will be applied in the subsequent request)
+     */
+    public setListRanges(index: number, ranges: number[][]): Promise<string> {
+        this.lists[index].updateListRange(ranges);
+        return this.resend();
+    }
+
+    /**
+     * Add or replace a list. Calling this function will interrupt the /sync request to resend new
+     * lists.
+     * @param index The index to modify
+     * @param list The new list parameters.
+     * @return A promise which resolves to the transaction ID when it has been received down sync
+     * (or rejects with the transaction ID if the action was not applied e.g the request was cancelled
+     * immediately after sending, in which case the action will be applied in the subsequent request)
+     */
+    public setList(index: number, list: MSC3575List): Promise<string> {
+        if (this.lists[index]) {
+            this.lists[index].replaceList(list);
+        } else {
+            this.lists[index] = new SlidingList(list);
+        }
+        this.listModifiedCount += 1;
+        return this.resend();
+    }
+
+    /**
+     * Get the room subscriptions for the sync API.
+     * @returns A copy of the desired room subscriptions.
+     */
+    public getRoomSubscriptions(): Set<string> {
+        return new Set(Array.from(this.desiredRoomSubscriptions));
+    }
+
+    /**
+     * Modify the room subscriptions for the sync API. Calling this function will interrupt the
+     * /sync request to resend new subscriptions. If the /sync stream has not started, this will
+     * prepare the room subscriptions for when start() is called.
+     * @param s The new desired room subscriptions.
+     * @return A promise which resolves to the transaction ID when it has been received down sync
+     * (or rejects with the transaction ID if the action was not applied e.g the request was cancelled
+     * immediately after sending, in which case the action will be applied in the subsequent request)
+     */
+    public modifyRoomSubscriptions(s: Set<string>): Promise<string> {
+        this.desiredRoomSubscriptions = s;
+        return this.resend();
+    }
+
+    /**
+     * Modify which events to retrieve for room subscriptions. Invalidates all room subscriptions
+     * such that they will be sent up afresh.
+     * @param rs The new room subscription fields to fetch.
+     * @return A promise which resolves to the transaction ID when it has been received down sync
+     * (or rejects with the transaction ID if the action was not applied e.g the request was cancelled
+     * immediately after sending, in which case the action will be applied in the subsequent request)
+     */
+    public modifyRoomSubscriptionInfo(rs: MSC3575RoomSubscription): Promise<string> {
+        this.roomSubscriptionInfo = rs;
+        this.confirmedRoomSubscriptions = new Set<string>();
+        return this.resend();
+    }
+
+    /**
+     * Register an extension to send with the /sync request.
+     * @param ext The extension to register.
+     */
+    public registerExtension(ext: Extension): void {
+        if (this.extensions[ext.name()]) {
+            throw new Error(`registerExtension: ${ext.name()} already exists as an extension`);
+        }
+        this.extensions[ext.name()] = ext;
+    }
+
+    private getExtensionRequest(isInitial: boolean): object {
+        const ext = {};
+        Object.keys(this.extensions).forEach((extName) => {
+            ext[extName] = this.extensions[extName].onRequest(isInitial);
+        });
+        return ext;
+    }
+
+    private onPreExtensionsResponse(ext: object): void {
+        Object.keys(ext).forEach((extName) => {
+            if (this.extensions[extName].when() == ExtensionState.PreProcess) {
+                this.extensions[extName].onResponse(ext[extName]);
+            }
+        });
+    }
+
+    private onPostExtensionsResponse(ext: object): void {
+        Object.keys(ext).forEach((extName) => {
+            if (this.extensions[extName].when() == ExtensionState.PostProcess) {
+                this.extensions[extName].onResponse(ext[extName]);
+            }
+        });
+    }
+
+    /**
+     * Invoke all attached room data listeners.
+     * @param {string} roomId The room which received some data.
+     * @param {object} roomData The raw sliding sync response JSON.
+     */
+    private invokeRoomDataListeners(roomId: string, roomData: MSC3575RoomData): void {
+        if (!roomData.required_state) { roomData.required_state = []; }
+        if (!roomData.timeline) { roomData.timeline = []; }
+        this.emit(SlidingSyncEvent.RoomData, roomId, roomData);
+    }
+
+    /**
+     * Invoke all attached lifecycle listeners.
+     * @param {SlidingSyncState} state The Lifecycle state
+     * @param {object} resp The raw sync response JSON
+     * @param {Error?} err Any error that occurred when making the request e.g. network errors.
+     */
+    private invokeLifecycleListeners(state: SlidingSyncState, resp: MSC3575SlidingSyncResponse, err?: Error): void {
+        this.emit(SlidingSyncEvent.Lifecycle, state, resp, err);
+    }
+
+    private shiftRight(listIndex: number, hi: number, low: number) {
+        //     l   h
+        // 0,1,2,3,4 <- before
+        // 0,1,2,2,3 <- after, hi is deleted and low is duplicated
+        for (let i = hi; i > low; i--) {
+            if (this.lists[listIndex].isIndexInRange(i)) {
+                this.lists[listIndex].roomIndexToRoomId[i] =
+                    this.lists[listIndex].roomIndexToRoomId[
+                        i - 1
+                    ];
+            }
+        }
+    }
+
+    private shiftLeft(listIndex: number, hi: number, low: number) {
+        //     l   h
+        // 0,1,2,3,4 <- before
+        // 0,1,3,4,4 <- after, low is deleted and hi is duplicated
+        for (let i = low; i < hi; i++) {
+            if (this.lists[listIndex].isIndexInRange(i)) {
+                this.lists[listIndex].roomIndexToRoomId[i] =
+                    this.lists[listIndex].roomIndexToRoomId[
+                        i + 1
+                    ];
+            }
+        }
+    }
+
+    private removeEntry(listIndex: number, index: number) {
+        // work out the max index
+        let max = -1;
+        for (const n in this.lists[listIndex].roomIndexToRoomId) {
+            if (Number(n) > max) {
+                max = Number(n);
+            }
+        }
+        if (max < 0 || index > max) {
+            return;
+        }
+        // Everything higher than the gap needs to be shifted left.
+        this.shiftLeft(listIndex, max, index);
+        delete this.lists[listIndex].roomIndexToRoomId[max];
+    }
+
+    private addEntry(listIndex: number, index: number) {
+        // work out the max index
+        let max = -1;
+        for (const n in this.lists[listIndex].roomIndexToRoomId) {
+            if (Number(n) > max) {
+                max = Number(n);
+            }
+        }
+        if (max < 0 || index > max) {
+            return;
+        }
+        // Everything higher than the gap needs to be shifted right, +1 so we don't delete the highest element
+        this.shiftRight(listIndex, max+1, index);
+    }
+
+    private processListOps(list: ListResponse, listIndex: number): void {
+        let gapIndex = -1;
+        list.ops.forEach((op: Operation) => {
+            switch (op.op) {
+                case "DELETE": {
+                    logger.debug("DELETE", listIndex, op.index, ";");
+                    delete this.lists[listIndex].roomIndexToRoomId[op.index];
+                    if (gapIndex !== -1) {
+                        // we already have a DELETE operation to process, so process it.
+                        this.removeEntry(listIndex, gapIndex);
+                    }
+                    gapIndex = op.index;
+                    break;
+                }
+                case "INSERT": {
+                    logger.debug(
+                        "INSERT",
+                        listIndex,
+                        op.index,
+                        op.room_id,
+                        ";",
+                    );
+                    if (this.lists[listIndex].roomIndexToRoomId[op.index]) {
+                        // something is in this space, shift items out of the way
+                        if (gapIndex < 0) {
+                            // we haven't been told where to shift from, so make way for a new room entry.
+                            this.addEntry(listIndex, op.index);
+                        } else if (gapIndex > op.index) {
+                            // the gap is further down the list, shift every element to the right
+                            // starting at the gap so we can just shift each element in turn:
+                            // [A,B,C,_] gapIndex=3, op.index=0
+                            // [A,B,C,C] i=3
+                            // [A,B,B,C] i=2
+                            // [A,A,B,C] i=1
+                            // Terminate. We'll assign into op.index next.
+                            this.shiftRight(listIndex, gapIndex, op.index);
+                        } else if (gapIndex < op.index) {
+                            // the gap is further up the list, shift every element to the left
+                            // starting at the gap so we can just shift each element in turn
+                            this.shiftLeft(listIndex, op.index, gapIndex);
+                        }
+                        gapIndex = -1; // forget the gap, we don't need it anymore.
+                    }
+                    this.lists[listIndex].roomIndexToRoomId[op.index] = op.room_id;
+                    break;
+                }
+                case "INVALIDATE": {
+                    const startIndex = op.range[0];
+                    for (let i = startIndex; i <= op.range[1]; i++) {
+                        delete this.lists[listIndex].roomIndexToRoomId[i];
+                    }
+                    logger.debug(
+                        "INVALIDATE",
+                        listIndex,
+                        op.range[0],
+                        op.range[1],
+                        ";",
+                    );
+                    break;
+                }
+                case "SYNC": {
+                    const startIndex = op.range[0];
+                    for (let i = startIndex; i <= op.range[1]; i++) {
+                        const roomId = op.room_ids[i - startIndex];
+                        if (!roomId) {
+                            break; // we are at the end of list
+                        }
+                        this.lists[listIndex].roomIndexToRoomId[i] = roomId;
+                    }
+                    logger.debug(
+                        "SYNC",
+                        listIndex,
+                        op.range[0],
+                        op.range[1],
+                        (op.room_ids || []).join(" "),
+                        ";",
+                    );
+                    break;
+                }
+            }
+        });
+        if (gapIndex !== -1) {
+            // we already have a DELETE operation to process, so process it
+            // Everything higher than the gap needs to be shifted left.
+            this.removeEntry(listIndex, gapIndex);
+        }
+    }
+
+    /**
+     * Resend a Sliding Sync request. Used when something has changed in the request. Resolves with
+     * the transaction ID of this request on success. Rejects with the transaction ID of this request
+     * on failure.
+     */
+    public resend(): Promise<string> {
+        if (this.needsResend && this.txnIdDefers.length > 0) {
+            // we already have a resend queued, so just return the same promise
+            return this.txnIdDefers[this.txnIdDefers.length-1].promise;
+        }
+        this.needsResend = true;
+        this.txnId = this.client.makeTxnId();
+        const d = defer<string>();
+        this.txnIdDefers.push({
+            ...d,
+            txnId: this.txnId,
+        });
+        this.pendingReq?.abort();
+        return d.promise;
+    }
+
+    private resolveTransactionDefers(txnId?: string) {
+        if (!txnId) {
+            return;
+        }
+        // find the matching index
+        let txnIndex = -1;
+        for (let i = 0; i < this.txnIdDefers.length; i++) {
+            if (this.txnIdDefers[i].txnId === txnId) {
+                txnIndex = i;
+                break;
+            }
+        }
+        if (txnIndex === -1) {
+            // this shouldn't happen; we shouldn't be seeing txn_ids for things we don't know about,
+            // whine about it.
+            logger.warn(`resolveTransactionDefers: seen ${txnId} but it isn't a pending txn, ignoring.`);
+            return;
+        }
+        // This list is sorted in time, so if the input txnId ACKs in the middle of this array,
+        // then everything before it that hasn't been ACKed yet never will and we should reject them.
+        for (let i = 0; i < txnIndex; i++) {
+            this.txnIdDefers[i].reject(this.txnIdDefers[i].txnId);
+        }
+        this.txnIdDefers[txnIndex].resolve(txnId);
+        // clear out settled promises, incuding the one we resolved.
+        this.txnIdDefers = this.txnIdDefers.slice(txnIndex+1);
+    }
+
+    /**
+     * Stop syncing with the server.
+     */
+    public stop(): void {
+        this.terminated = true;
+        this.pendingReq?.abort();
+        // remove all listeners so things can be GC'd
+        this.removeAllListeners(SlidingSyncEvent.Lifecycle);
+        this.removeAllListeners(SlidingSyncEvent.List);
+        this.removeAllListeners(SlidingSyncEvent.RoomData);
+    }
+
+    /**
+     * Start syncing with the server. Blocks until stopped.
+     */
+    public async start() {
+        let currentPos: string;
+        while (!this.terminated) {
+            this.needsResend = false;
+            let doNotUpdateList = false;
+            let resp: MSC3575SlidingSyncResponse;
+            try {
+                const listModifiedCount = this.listModifiedCount;
+                const reqBody: MSC3575SlidingSyncRequest = {
+                    lists: this.lists.map((l) => {
+                        return l.getList(false);
+                    }),
+                    pos: currentPos,
+                    timeout: this.timeoutMS,
+                    clientTimeout: this.timeoutMS + BUFFER_PERIOD_MS,
+                    extensions: this.getExtensionRequest(currentPos === undefined),
+                };
+                // check if we are (un)subscribing to a room and modify request this one time for it
+                const newSubscriptions = difference(this.desiredRoomSubscriptions, this.confirmedRoomSubscriptions);
+                const unsubscriptions = difference(this.confirmedRoomSubscriptions, this.desiredRoomSubscriptions);
+                if (unsubscriptions.size > 0) {
+                    reqBody.unsubscribe_rooms = Array.from(unsubscriptions);
+                }
+                if (newSubscriptions.size > 0) {
+                    reqBody.room_subscriptions = {};
+                    for (const roomId of newSubscriptions) {
+                        reqBody.room_subscriptions[roomId] = this.roomSubscriptionInfo;
+                    }
+                }
+                if (this.txnId) {
+                    reqBody.txn_id = this.txnId;
+                    this.txnId = null;
+                }
+                this.pendingReq = this.client.slidingSync(reqBody, this.proxyBaseUrl);
+                resp = await this.pendingReq;
+                logger.debug(resp);
+                currentPos = resp.pos;
+                // update what we think we're subscribed to.
+                for (const roomId of newSubscriptions) {
+                    this.confirmedRoomSubscriptions.add(roomId);
+                }
+                for (const roomId of unsubscriptions) {
+                    this.confirmedRoomSubscriptions.delete(roomId);
+                }
+                if (listModifiedCount !== this.listModifiedCount) {
+                    // the lists have been modified whilst we were waiting for 'await' to return, but the abort()
+                    // call did nothing. It is NOT SAFE to modify the list array now. We'll process the response but
+                    // not update list pointers.
+                    logger.debug("list modified during await call, not updating list");
+                    doNotUpdateList = true;
+                }
+                // mark all these lists as having been sent as sticky so we don't keep sending sticky params
+                this.lists.forEach((l) => {
+                    l.setModified(false);
+                });
+                // set default empty values so we don't need to null check
+                resp.lists = resp.lists || [];
+                resp.rooms = resp.rooms || {};
+                resp.extensions = resp.extensions || {};
+                resp.lists.forEach((val, i) => {
+                    this.lists[i].joinedCount = val.count;
+                });
+                this.invokeLifecycleListeners(
+                    SlidingSyncState.RequestFinished,
+                    resp,
+                );
+            } catch (err) {
+                if (err.httpStatus) {
+                    this.invokeLifecycleListeners(
+                        SlidingSyncState.RequestFinished,
+                        null,
+                        err,
+                    );
+                    await sleep(3000);
+                } else if (this.needsResend || err === "aborted") {
+                    // don't sleep as we caused this error by abort()ing the request.
+                    // we check for 'aborted' because that's the error Jest returns and without it
+                    // we get warnings about not exiting fast enough.
+                    continue;
+                } else {
+                    logger.error(err);
+                    await sleep(3000);
+                }
+            }
+            if (!resp) {
+                continue;
+            }
+            this.onPreExtensionsResponse(resp.extensions);
+
+            Object.keys(resp.rooms).forEach((roomId) => {
+                this.invokeRoomDataListeners(
+                    roomId,
+                    resp.rooms[roomId],
+                );
+            });
+
+            const listIndexesWithUpdates: Set<number> = new Set();
+            if (!doNotUpdateList) {
+                resp.lists.forEach((list, listIndex) => {
+                    list.ops = list.ops || [];
+                    if (list.ops.length > 0) {
+                        listIndexesWithUpdates.add(listIndex);
+                    }
+                    this.processListOps(list, listIndex);
+                });
+            }
+            this.invokeLifecycleListeners(SlidingSyncState.Complete, resp);
+            this.onPostExtensionsResponse(resp.extensions);
+            listIndexesWithUpdates.forEach((i) => {
+                this.emit(
+                    SlidingSyncEvent.List,
+                    i, this.lists[i].joinedCount, Object.assign({}, this.lists[i].roomIndexToRoomId),
+                );
+            });
+
+            this.resolveTransactionDefers(resp.txn_id);
+        }
+    }
+}
+
+const difference = (setA: Set<string>, setB: Set<string>): Set<string> => {
+    const diff = new Set(setA);
+    for (const elem of setB) {
+        diff.delete(elem);
+    }
+    return diff;
+};
@@ -23,6 +23,7 @@ import { RoomSummary } from "../models/room-summary";
 import { IMinimalEvent, IRooms, ISyncResponse } from "../sync-accumulator";
 import { IStartClientOpts } from "../client";
 import { IStateEventWithRoomId } from "../@types/search";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

 export interface ISavedSync {
    nextBatch: string;
@@ -31,8 +32,7 @@ export interface ISavedSync {
 }

 /**
- * Construct a stub store. This does no-ops on most store methods.
- * @constructor
+ * A store for most of the data js-sdk needs to store, apart from crypto data
 */
 export interface IStore {
    readonly accountData: Record<string, MatrixEvent>; // type : content
@@ -57,21 +57,21 @@ export interface IStore {
    setSyncToken(token: string): void;

    /**
-     * No-op.
-     * @param {Room} room
+     * Store the given room.
+     * @param {Room} room The room to be stored. All properties must be stored.
     */
    storeRoom(room: Room): void;

    /**
-     * No-op.
-     * @param {string} roomId
-     * @return {null}
+     * Retrieve a room by its' room ID.
+     * @param {string} roomId The room ID.
+     * @return {Room} The room or null.
     */
    getRoom(roomId: string): Room | null;

    /**
-     * No-op.
-     * @return {Array} An empty array.
+     * Retrieve all known rooms.
+     * @return {Room[]} A list of rooms, which may be empty.
     */
    getRooms(): Room[];

@@ -82,35 +82,36 @@ export interface IStore {
    removeRoom(roomId: string): void;

    /**
-     * No-op.
-     * @return {Array} An empty array.
+     * Retrieve a summary of all the rooms.
+     * @return {RoomSummary[]} A summary of each room.
     */
    getRoomSummaries(): RoomSummary[];

    /**
-     * No-op.
-     * @param {User} user
+     * Store a User.
+     * @param {User} user The user to store.
     */
    storeUser(user: User): void;

    /**
-     * No-op.
-     * @param {string} userId
-     * @return {null}
+     * Retrieve a User by its' user ID.
+     * @param {string} userId The user ID.
+     * @return {User} The user or null.
     */
    getUser(userId: string): User | null;

    /**
-     * No-op.
-     * @return {User[]}
+     * Retrieve all known users.
+     * @return {User[]} A list of users, which may be empty.
     */
    getUsers(): User[];

    /**
-     * No-op.
-     * @param {Room} room
-     * @param {number} limit
-     * @return {Array}
+     * Retrieve scrollback for this room.
+     * @param {Room} room The matrix room
+     * @param {number} limit The max number of old events to retrieve.
+     * @return {Array<Object>} An array of objects which will be at most 'limit'
+     * length and at least 0. The objects are the raw event JSON.
     */
    scrollback(room: Room, limit: number): MatrixEvent[];

@@ -209,8 +210,23 @@ export interface IStore {
     */
    deleteAllData(): Promise<void>;

+    /**
+     * Returns the out-of-band membership events for this room that
+     * were previously loaded.
+     * @param {string} roomId
+     * @returns {event[]} the events, potentially an empty array if OOB loading didn't yield any new members
+     * @returns {null} in case the members for this room haven't been stored yet
+     */
    getOutOfBandMembers(roomId: string): Promise<IStateEventWithRoomId[] | null>;

+    /**
+     * Stores the out-of-band membership events for this room. Note that
+     * it still makes sense to store an empty array as the OOB status for the room is
+     * marked as fetched, and getOutOfBandMembers will return an empty array instead of null
+     * @param {string} roomId
+     * @param {event[]} membershipEvents the membership events to store
+     * @returns {Promise} when all members have been stored
+     */
    setOutOfBandMembers(roomId: string, membershipEvents: IStateEventWithRoomId[]): Promise<void>;

    clearOutOfBandMembers(roomId: string): Promise<void>;
@@ -222,4 +238,19 @@ export interface IStore {
    getPendingEvents(roomId: string): Promise<Partial<IEvent>[]>;

    setPendingEvents(roomId: string, events: Partial<IEvent>[]): Promise<void>;
+
+    /**
+     * Stores batches of outgoing to-device messages
+     */
+     saveToDeviceBatches(batch: ToDeviceBatchWithTxnId[]): Promise<void>;
+
+     /**
+      * Fetches the oldest batch of to-device messages in the queue
+      */
+     getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch>;
+
+     /**
+      * Removes a specific batch of to-device messages from the queue
+      */
+     removeToDeviceBatch(id: number): Promise<void>;
 }
@@ -16,6 +16,7 @@ limitations under the License.

 import { ISavedSync } from "./index";
 import { IEvent, IStartClientOpts, IStateEventWithRoomId, ISyncResponse } from "..";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

 export interface IIndexedDBBackend {
    connect(): Promise<void>;
@@ -31,6 +32,9 @@ export interface IIndexedDBBackend {
    getUserPresenceEvents(): Promise<UserTuple[]>;
    getClientOptions(): Promise<IStartClientOpts>;
    storeClientOptions(options: IStartClientOpts): Promise<void>;
+    saveToDeviceBatches(batches: ToDeviceBatchWithTxnId[]): Promise<void>;
+    getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch>;
+    removeToDeviceBatch(id: number): Promise<void>;
 }

 export type UserTuple = [userId: string, presenceEvent: Partial<IEvent>];
@@ -21,8 +21,9 @@ import { logger } from '../logger';
 import { IStartClientOpts, IStateEventWithRoomId } from "..";
 import { ISavedSync } from "./index";
 import { IIndexedDBBackend, UserTuple } from "./indexeddb-backend";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

-const VERSION = 3;
+const VERSION = 4;

 function createDatabase(db: IDBDatabase): void {
    // Make user store, clobber based on user ID. (userId property of User objects)
@@ -49,6 +50,10 @@ function upgradeSchemaV3(db: IDBDatabase): void {
        { keyPath: ["clobber"] });
 }

+function upgradeSchemaV4(db: IDBDatabase): void {
+    db.createObjectStore("to_device_queue", { autoIncrement: true });
+}
+
 /**
 * Helper method to collect results from a Cursor and promiseify it.
 * @param {ObjectStore|Index} store The store to perform openCursor on.
@@ -112,7 +117,7 @@ function reqAsPromise(req: IDBRequest): Promise<IDBRequest> {
    });
 }

-function reqAsCursorPromise(req: IDBRequest<IDBCursor | null>): Promise<IDBCursor> {
+function reqAsCursorPromise<T>(req: IDBRequest<T>): Promise<T> {
    return reqAsEventPromise(req).then((event) => req.result);
 }

@@ -177,6 +182,9 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
            if (oldVersion < 3) {
                upgradeSchemaV3(db);
            }
+            if (oldVersion < 4) {
+                upgradeSchemaV4(db);
+            }
            // Expand as needed.
        };

@@ -401,8 +409,6 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
    }

    public async syncToDatabase(userTuples: UserTuple[]): Promise<void> {
-        const syncData = this.syncAccumulator.getJSON(true);
-
        if (this.isPersisting) {
            logger.warn("Skipping syncToDatabase() as persist already in flight");
            this.pendingUserPresenceData.push(...userTuples);
@@ -413,6 +419,8 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
        }

        try {
+            const syncData = this.syncAccumulator.getJSON(true);
+
            await Promise.all([
                this.persistUserPresenceEvents(userTuples),
                this.persistAccountData(syncData.accountData),
@@ -561,4 +569,36 @@ export class LocalIndexedDBStoreBackend implements IIndexedDBBackend {
        }); // put == UPSERT
        await txnAsPromise(txn);
    }
+
+    public async saveToDeviceBatches(batches: ToDeviceBatchWithTxnId[]): Promise<void> {
+        const txn = this.db.transaction(["to_device_queue"], "readwrite");
+        const store = txn.objectStore("to_device_queue");
+        for (const batch of batches) {
+            store.add(batch);
+        }
+        await txnAsPromise(txn);
+    }
+
+    public async getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch | null> {
+        const txn = this.db.transaction(["to_device_queue"], "readonly");
+        const store = txn.objectStore("to_device_queue");
+        const cursor = await reqAsCursorPromise(store.openCursor());
+        if (!cursor) return null;
+
+        const resultBatch = cursor.value as ToDeviceBatchWithTxnId;
+
+        return {
+            id: cursor.key as number,
+            txnId: resultBatch.txnId,
+            eventType: resultBatch.eventType,
+            batch: resultBatch.batch,
+        };
+    }
+
+    public async removeToDeviceBatch(id: number): Promise<void> {
+        const txn = this.db.transaction(["to_device_queue"], "readwrite");
+        const store = txn.objectStore("to_device_queue");
+        store.delete(id);
+        await txnAsPromise(txn);
+    }
 }
@@ -20,6 +20,7 @@ import { ISavedSync } from "./index";
 import { IStartClientOpts } from "../client";
 import { IStateEventWithRoomId, ISyncResponse } from "..";
 import { IIndexedDBBackend, UserTuple } from "./indexeddb-backend";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

 export class RemoteIndexedDBStoreBackend implements IIndexedDBBackend {
    private worker: Worker;
@@ -133,6 +134,18 @@ export class RemoteIndexedDBStoreBackend implements IIndexedDBBackend {
        return this.doCmd('getUserPresenceEvents');
    }

+    public async saveToDeviceBatches(batches: ToDeviceBatchWithTxnId[]): Promise<void> {
+        return this.doCmd('saveToDeviceBatches', [batches]);
+    }
+
+    public async getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch> {
+        return this.doCmd('getOldestToDeviceBatch');
+    }
+
+    public async removeToDeviceBatch(id: number): Promise<void> {
+        return this.doCmd('removeToDeviceBatch', [id]);
+    }
+
    private ensureStarted(): Promise<void> {
        if (this.startPromise === null) {
            this.worker = this.workerFactory();
@@ -103,6 +103,15 @@ export class IndexedDBStoreWorker {
            case 'storeClientOptions':
                prom = this.backend.storeClientOptions(msg.args[0]);
                break;
+            case 'saveToDeviceBatches':
+                prom = this.backend.saveToDeviceBatches(msg.args[0]);
+                break;
+            case 'getOldestToDeviceBatch':
+                prom = this.backend.getOldestToDeviceBatch();
+                break;
+            case 'removeToDeviceBatch':
+                prom = this.backend.removeToDeviceBatch(msg.args[0]);
+                break;
        }

        if (prom === undefined) {
@@ -27,6 +27,7 @@ import { IIndexedDBBackend } from "./indexeddb-backend";
 import { ISyncResponse } from "../sync-accumulator";
 import { TypedEventEmitter } from "../models/typed-event-emitter";
 import { IStateEventWithRoomId } from "../@types/search";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

 /**
 * This is an internal module. See {@link IndexedDBStore} for the public class.
@@ -351,6 +352,18 @@ export class IndexedDBStore extends MemoryStore {
            this.localStorage.removeItem(pendingEventsKey(roomId));
        }
    }
+
+    public saveToDeviceBatches(batches: ToDeviceBatchWithTxnId[]): Promise<void> {
+        return this.backend.saveToDeviceBatches(batches);
+    }
+
+    public getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch> {
+        return this.backend.getOldestToDeviceBatch();
+    }
+
+    public removeToDeviceBatch(id: number): Promise<void> {
+        return this.backend.removeToDeviceBatch(id);
+    }
 }

 /**
@@ -30,6 +30,7 @@ import { ISavedSync, IStore } from "./index";
 import { RoomSummary } from "../models/room-summary";
 import { ISyncResponse } from "../sync-accumulator";
 import { IStateEventWithRoomId } from "../@types/search";
+import { IndexedToDeviceBatch, ToDeviceBatchWithTxnId } from "../models/ToDeviceMessage";

 function isValidFilterId(filterId: string): boolean {
    const isValidStr = typeof filterId === "string" &&
@@ -64,6 +65,8 @@ export class MemoryStore implements IStore {
    private oobMembers: Record<string, IStateEventWithRoomId[]> = {}; // roomId: [member events]
    private pendingEvents: { [roomId: string]: Partial<IEvent>[] } = {};
    private clientOptions = {};
+    private pendingToDeviceBatches: IndexedToDeviceBatch[] = [];
+    private nextToDeviceBatchId = 0;

    constructor(opts: IOpts = {}) {
        this.localStorage = opts.localStorage;
@@ -429,4 +432,26 @@ export class MemoryStore implements IStore {
    public async setPendingEvents(roomId: string, events: Partial<IEvent>[]): Promise<void> {
        this.pendingEvents[roomId] = events;
    }
+
+    public saveToDeviceBatches(batches: ToDeviceBatchWithTxnId[]): Promise<void> {
+        for (const batch of batches) {
+            this.pendingToDeviceBatches.push({
+                id: this.nextToDeviceBatchId++,
+                eventType: batch.eventType,
+                txnId: batch.txnId,
+                batch: batch.batch,
+            });
+        }
+        return Promise.resolve();
+    }
+
+    public async getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch | null> {
+        if (this.pendingToDeviceBatches.length === 0) return null;
+        return this.pendingToDeviceBatches[0];
+    }
+
+    public removeToDeviceBatch(id: number): Promise<void> {
+        this.pendingToDeviceBatches = this.pendingToDeviceBatches.filter(batch => batch.id !== id);
+        return Promise.resolve();
+    }
 }
@@ -28,6 +28,7 @@ import { ISavedSync, IStore } from "./index";
 import { RoomSummary } from "../models/room-summary";
 import { ISyncResponse } from "../sync-accumulator";
 import { IStateEventWithRoomId } from "../@types/search";
+import { IndexedToDeviceBatch, ToDeviceBatch } from "../models/ToDeviceMessage";

 /**
 * Construct a stub store. This does no-ops on most store methods.
@@ -270,4 +271,16 @@ export class StubStore implements IStore {
    public setPendingEvents(roomId: string, events: Partial<IEvent>[]): Promise<void> {
        return Promise.resolve();
    }
+
+    public async saveToDeviceBatches(batch: ToDeviceBatch[]): Promise<void> {
+        return Promise.resolve();
+    }
+
+    public getOldestToDeviceBatch(): Promise<IndexedToDeviceBatch | null> {
+        return Promise.resolve(null);
+    }
+
+    public async removeToDeviceBatch(id: number): Promise<void> {
+        return Promise.resolve();
+    }
 }
@@ -20,7 +20,7 @@ limitations under the License.
 */

 import { logger } from './logger';
-import { deepCopy } from "./utils";
+import { deepCopy, isSupportedReceiptType } from "./utils";
 import { IContent, IUnsigned } from "./models/event";
 import { IRoomSummary } from "./models/room-summary";
 import { EventType } from "./@types/event";
@@ -417,31 +417,18 @@ export class SyncAccumulator {
                // of a hassle to work with. We'll inflate this back out when
                // getJSON() is called.
                Object.keys(e.content).forEach((eventId) => {
-                    if (!e.content[eventId][ReceiptType.Read] && !e.content[eventId][ReceiptType.ReadPrivate]) {
-                        return;
-                    }
-                    const read = e.content[eventId][ReceiptType.Read];
-                    if (read) {
-                        Object.keys(read).forEach((userId) => {
+                    Object.entries(e.content[eventId]).forEach(([key, value]) => {
+                        if (!isSupportedReceiptType(key)) return;
+
+                        Object.keys(value).forEach((userId) => {
                            // clobber on user ID
                            currentData._readReceipts[userId] = {
-                                data: e.content[eventId][ReceiptType.Read][userId],
-                                type: ReceiptType.Read,
+                                data: e.content[eventId][key][userId],
+                                type: key as ReceiptType,
                                eventId: eventId,
                            };
                        });
-                    }
-                    const readPrivate = e.content[eventId][ReceiptType.ReadPrivate];
-                    if (readPrivate) {
-                        Object.keys(readPrivate).forEach((userId) => {
-                            // clobber on user ID
-                            currentData._readReceipts[userId] = {
-                                data: e.content[eventId][ReceiptType.ReadPrivate][userId],
-                                type: ReceiptType.ReadPrivate,
-                                eventId: eventId,
-                            };
-                        });
-                    }
+                    });
                });
            });
        }
@@ -1,5 +1,5 @@
 /*
-Copyright 2015 - 2021 The Matrix.org Foundation C.I.C.
+Copyright 2015 - 2022 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -23,6 +23,8 @@ limitations under the License.
 * for HTTP and WS at some point.
 */

+import { Optional } from "matrix-events-sdk";
+
 import { User, UserEvent } from "./models/user";
 import { NotificationCountType, Room, RoomEvent } from "./models/room";
 import * as utils from "./utils";
@@ -51,7 +53,7 @@ import { MatrixError, Method } from "./http-api";
 import { ISavedSync } from "./store";
 import { EventType } from "./@types/event";
 import { IPushRules } from "./@types/PushRules";
-import { RoomState, RoomStateEvent, IMarkerFoundOptions } from "./models/room-state";
+import { RoomStateEvent, IMarkerFoundOptions } from "./models/room-state";
 import { RoomMemberEvent } from "./models/room-member";
 import { BeaconEvent } from "./models/beacon";
 import { IEventsResponse } from "./@types/requests";
@@ -100,18 +102,16 @@ const MSC2716_ROOM_VERSIONS = [
 function getFilterName(userId: string, suffix?: string): string {
    // scope this on the user ID because people may login on many accounts
    // and they all need to be stored!
-    return "FILTER_SYNC_" + userId + (suffix ? "_" + suffix : "");
+    return `FILTER_SYNC_${userId}` + (suffix ? "_" + suffix : "");
 }

 function debuglog(...params) {
-    if (!DEBUG) {
-        return;
-    }
+    if (!DEBUG) return;
    logger.log(...params);
 }

 interface ISyncOptions {
-    filterId?: string;
+    filter?: string;
    hasSyncedBefore?: boolean;
 }

@@ -161,14 +161,14 @@ type WrappedRoom<T> = T & {
 * updating presence.
 */
 export class SyncApi {
-    private _peekRoom: Room = null;
-    private currentSyncRequest: IAbortablePromise<ISyncResponse> = null;
-    private syncState: SyncState = null;
-    private syncStateData: ISyncStateData = null; // additional data (eg. error object for failed sync)
+    private _peekRoom: Optional<Room> = null;
+    private currentSyncRequest: Optional<IAbortablePromise<ISyncResponse>> = null;
+    private syncState: Optional<SyncState> = null;
+    private syncStateData: Optional<ISyncStateData> = null; // additional data (eg. error object for failed sync)
    private catchingUp = false;
    private running = false;
-    private keepAliveTimer: ReturnType<typeof setTimeout> = null;
-    private connectionReturnedDefer: IDeferred<boolean> = null;
+    private keepAliveTimer: Optional<ReturnType<typeof setTimeout>> = null;
+    private connectionReturnedDefer: Optional<IDeferred<boolean>> = null;
    private notifEvents: MatrixEvent[] = []; // accumulator of sync events in the current sync response
    private failedSyncCount = 0; // Number of consecutive failed /sync requests
    private storeIsInvalid = false; // flag set if the store needs to be cleared before we can start
@@ -199,85 +199,13 @@ export class SyncApi {
     * @return {Room}
     */
    public createRoom(roomId: string): Room {
-        const client = this.client;
-        const {
-            timelineSupport,
-        } = client;
-        const room = new Room(roomId, client, client.getUserId(), {
-            lazyLoadMembers: this.opts.lazyLoadMembers,
-            pendingEventOrdering: this.opts.pendingEventOrdering,
-            timelineSupport,
-        });
-        client.reEmitter.reEmit(room, [
-            RoomEvent.Name,
-            RoomEvent.Redaction,
-            RoomEvent.RedactionCancelled,
-            RoomEvent.Receipt,
-            RoomEvent.Tags,
-            RoomEvent.LocalEchoUpdated,
-            RoomEvent.AccountData,
-            RoomEvent.MyMembership,
-            RoomEvent.Timeline,
-            RoomEvent.TimelineReset,
-        ]);
-        this.registerStateListeners(room);
-        // Register listeners again after the state reference changes
-        room.on(RoomEvent.CurrentStateUpdated, (targetRoom, previousCurrentState) => {
-            if (targetRoom !== room) {
-                return;
-            }
+        const room = _createAndReEmitRoom(this.client, roomId, this.opts);

-            this.deregisterStateListeners(previousCurrentState);
-            this.registerStateListeners(room);
-        });
-        return room;
-    }
-
-    /**
-     * @param {Room} room
-     * @private
-     */
-    private registerStateListeners(room: Room): void {
-        const client = this.client;
-        // we need to also re-emit room state and room member events, so hook it up
-        // to the client now. We need to add a listener for RoomState.members in
-        // order to hook them correctly. (TODO: find a better way?)
-        client.reEmitter.reEmit(room.currentState, [
-            RoomStateEvent.Events,
-            RoomStateEvent.Members,
-            RoomStateEvent.NewMember,
-            RoomStateEvent.Update,
-            BeaconEvent.New,
-            BeaconEvent.Update,
-            BeaconEvent.Destroy,
-            BeaconEvent.LivenessChange,
-        ]);
-
-        room.currentState.on(RoomStateEvent.NewMember, function(event, state, member) {
-            member.user = client.getUser(member.userId);
-            client.reEmitter.reEmit(member, [
-                RoomMemberEvent.Name,
-                RoomMemberEvent.Typing,
-                RoomMemberEvent.PowerLevel,
-                RoomMemberEvent.Membership,
-            ]);
-        });
-
-        room.currentState.on(RoomStateEvent.Marker, (markerEvent, markerFoundOptions) => {
+        room.on(RoomStateEvent.Marker, (markerEvent, markerFoundOptions) => {
            this.onMarkerStateEvent(room, markerEvent, markerFoundOptions);
        });
-    }

-    /**
-     * @param {RoomState} roomState The roomState to clear listeners from
-     * @private
-     */
-    private deregisterStateListeners(roomState: RoomState): void {
-        // could do with a better way of achieving this.
-        roomState.removeAllListeners(RoomStateEvent.Events);
-        roomState.removeAllListeners(RoomStateEvent.Members);
-        roomState.removeAllListeners(RoomStateEvent.NewMember);
-        roomState.removeAllListeners(RoomStateEvent.Marker);
+        return room;
    }

    /** When we see the marker state change in the room, we know there is some
@@ -286,7 +214,7 @@ export class SyncApi {
     * historical messages are shown when we paginate `/messages` again.
     * @param {Room} room The room where the marker event was sent
     * @param {MatrixEvent} markerEvent The new marker event
-     * @param {ISetStateOptions} setStateOptions When `timelineWasEmpty` is set
+     * @param {IMarkerFoundOptions} setStateOptions When `timelineWasEmpty` is set
     * as `true`, the given marker event will be ignored
    */
    private onMarkerStateEvent(
@@ -439,7 +367,7 @@ export class SyncApi {

            // XXX: copypasted from /sync until we kill off this minging v1 API stuff)
            // handle presence events (User objects)
-            if (response.presence && Array.isArray(response.presence)) {
+            if (Array.isArray(response.presence)) {
                response.presence.map(client.getEventMapper()).forEach(
                    function(presenceEvent) {
                        let user = client.store.getUser(presenceEvent.getContent().user_id);
@@ -614,20 +542,135 @@ export class SyncApi {
        return false;
    }

+    private getPushRules = async () => {
+        try {
+            debuglog("Getting push rules...");
+            const result = await this.client.getPushRules();
+            debuglog("Got push rules");
+
+            this.client.pushRules = result;
+        } catch (err) {
+            logger.error("Getting push rules failed", err);
+            if (this.shouldAbortSync(err)) return;
+            // wait for saved sync to complete before doing anything else,
+            // otherwise the sync state will end up being incorrect
+            debuglog("Waiting for saved sync before retrying push rules...");
+            await this.recoverFromSyncStartupError(this.savedSyncPromise, err);
+            return this.getPushRules(); // try again
+        }
+    };
+
+    private buildDefaultFilter = () => {
+        return new Filter(this.client.credentials.userId);
+    };
+
+    private checkLazyLoadStatus = async () => {
+        debuglog("Checking lazy load status...");
+        if (this.opts.lazyLoadMembers && this.client.isGuest()) {
+            this.opts.lazyLoadMembers = false;
+        }
+        if (this.opts.lazyLoadMembers) {
+            debuglog("Checking server lazy load support...");
+            const supported = await this.client.doesServerSupportLazyLoading();
+            if (supported) {
+                debuglog("Enabling lazy load on sync filter...");
+                if (!this.opts.filter) {
+                    this.opts.filter = this.buildDefaultFilter();
+                }
+                this.opts.filter.setLazyLoadMembers(true);
+            } else {
+                debuglog("LL: lazy loading requested but not supported " +
+                    "by server, so disabling");
+                this.opts.lazyLoadMembers = false;
+            }
+        }
+        // need to vape the store when enabling LL and wasn't enabled before
+        debuglog("Checking whether lazy loading has changed in store...");
+        const shouldClear = await this.wasLazyLoadingToggled(this.opts.lazyLoadMembers);
+        if (shouldClear) {
+            this.storeIsInvalid = true;
+            const reason = InvalidStoreError.TOGGLED_LAZY_LOADING;
+            const error = new InvalidStoreError(reason, !!this.opts.lazyLoadMembers);
+            this.updateSyncState(SyncState.Error, { error });
+            // bail out of the sync loop now: the app needs to respond to this error.
+            // we leave the state as 'ERROR' which isn't great since this normally means
+            // we're retrying. The client must be stopped before clearing the stores anyway
+            // so the app should stop the client, clear the store and start it again.
+            logger.warn("InvalidStoreError: store is not usable: stopping sync.");
+            return;
+        }
+        if (this.opts.lazyLoadMembers) {
+            this.opts.crypto?.enableLazyLoading();
+        }
+        try {
+            debuglog("Storing client options...");
+            await this.client.storeClientOptions();
+            debuglog("Stored client options");
+        } catch (err) {
+            logger.error("Storing client options failed", err);
+            throw err;
+        }
+    };
+
+    private getFilter = async (): Promise<{
+        filterId?: string;
+        filter?: Filter;
+    }> => {
+        debuglog("Getting filter...");
+        let filter: Filter;
+        if (this.opts.filter) {
+            filter = this.opts.filter;
+        } else {
+            filter = this.buildDefaultFilter();
+        }
+
+        let filterId: string;
+        try {
+            filterId = await this.client.getOrCreateFilter(getFilterName(this.client.credentials.userId), filter);
+        } catch (err) {
+            logger.error("Getting filter failed", err);
+            if (this.shouldAbortSync(err)) return {};
+            // wait for saved sync to complete before doing anything else,
+            // otherwise the sync state will end up being incorrect
+            debuglog("Waiting for saved sync before retrying filter...");
+            await this.recoverFromSyncStartupError(this.savedSyncPromise, err);
+            return this.getFilter(); // try again
+        }
+        return { filter, filterId };
+    };
+
+    private savedSyncPromise: Promise<void>;
+
    /**
     * Main entry point
     */
-    public sync(): void {
-        const client = this.client;
-
+    public async sync(): Promise<void> {
        this.running = true;

-        if (global.window && global.window.addEventListener) {
-            global.window.addEventListener("online", this.onOnline, false);
+        global.window?.addEventListener?.("online", this.onOnline, false);
+
+        if (this.client.isGuest()) {
+            // no push rules for guests, no access to POST filter for guests.
+            return this.doSync({});
        }

-        let savedSyncPromise = Promise.resolve();
-        let savedSyncToken = null;
+        // Pull the saved sync token out first, before the worker starts sending
+        // all the sync data which could take a while. This will let us send our
+        // first incremental sync request before we've processed our saved data.
+        debuglog("Getting saved sync token...");
+        const savedSyncTokenPromise = this.client.store.getSavedSyncToken().then(tok => {
+            debuglog("Got saved sync token");
+            return tok;
+        });
+
+        this.savedSyncPromise = this.client.store.getSavedSync().then((savedSync) => {
+            debuglog(`Got reply from saved sync, exists? ${!!savedSync}`);
+            if (savedSync) {
+                return this.syncFromCache(savedSync);
+            }
+        }).catch(err => {
+            logger.error("Getting saved sync failed", err);
+        });

        // We need to do one-off checks before we can begin the /sync loop.
        // These are:
@@ -637,149 +680,45 @@ export class SyncApi {
        //   3) We need to check the lazy loading option matches what was used in the
        //       stored sync. If it doesn't, we can't use the stored sync.

-        const getPushRules = async () => {
-            try {
-                debuglog("Getting push rules...");
-                const result = await client.getPushRules();
-                debuglog("Got push rules");
+        // Now start the first incremental sync request: this can also
+        // take a while so if we set it going now, we can wait for it
+        // to finish while we process our saved sync data.
+        await this.getPushRules();
+        await this.checkLazyLoadStatus();
+        const { filterId, filter } = await this.getFilter();
+        if (!filter) return; // bail, getFilter failed

-                client.pushRules = result;
-            } catch (err) {
-                logger.error("Getting push rules failed", err);
-                if (this.shouldAbortSync(err)) return;
-                // wait for saved sync to complete before doing anything else,
-                // otherwise the sync state will end up being incorrect
-                debuglog("Waiting for saved sync before retrying push rules...");
-                await this.recoverFromSyncStartupError(savedSyncPromise, err);
-                getPushRules();
-                return;
-            }
-            checkLazyLoadStatus(); // advance to the next stage
-        };
+        // reset the notifications timeline to prepare it to paginate from
+        // the current point in time.
+        // The right solution would be to tie /sync pagination tokens into
+        // /notifications API somehow.
+        this.client.resetNotifTimelineSet();

-        const buildDefaultFilter = () => {
-            const filter = new Filter(client.credentials.userId);
-            filter.setTimelineLimit(this.opts.initialSyncLimit);
-            return filter;
-        };
+        if (this.currentSyncRequest === null) {
+            let firstSyncFilter = filterId;
+            const savedSyncToken = await savedSyncTokenPromise;

-        const checkLazyLoadStatus = async () => {
-            debuglog("Checking lazy load status...");
-            if (this.opts.lazyLoadMembers && client.isGuest()) {
-                this.opts.lazyLoadMembers = false;
-            }
-            if (this.opts.lazyLoadMembers) {
-                debuglog("Checking server lazy load support...");
-                const supported = await client.doesServerSupportLazyLoading();
-                if (supported) {
-                    debuglog("Enabling lazy load on sync filter...");
-                    if (!this.opts.filter) {
-                        this.opts.filter = buildDefaultFilter();
-                    }
-                    this.opts.filter.setLazyLoadMembers(true);
-                } else {
-                    debuglog("LL: lazy loading requested but not supported " +
-                        "by server, so disabling");
-                    this.opts.lazyLoadMembers = false;
-                }
-            }
-            // need to vape the store when enabling LL and wasn't enabled before
-            debuglog("Checking whether lazy loading has changed in store...");
-            const shouldClear = await this.wasLazyLoadingToggled(this.opts.lazyLoadMembers);
-            if (shouldClear) {
-                this.storeIsInvalid = true;
-                const reason = InvalidStoreError.TOGGLED_LAZY_LOADING;
-                const error = new InvalidStoreError(reason, !!this.opts.lazyLoadMembers);
-                this.updateSyncState(SyncState.Error, { error });
-                // bail out of the sync loop now: the app needs to respond to this error.
-                // we leave the state as 'ERROR' which isn't great since this normally means
-                // we're retrying. The client must be stopped before clearing the stores anyway
-                // so the app should stop the client, clear the store and start it again.
-                logger.warn("InvalidStoreError: store is not usable: stopping sync.");
-                return;
-            }
-            if (this.opts.lazyLoadMembers && this.opts.crypto) {
-                this.opts.crypto.enableLazyLoading();
-            }
-            try {
-                debuglog("Storing client options...");
-                await this.client.storeClientOptions();
-                debuglog("Stored client options");
-            } catch (err) {
-                logger.error("Storing client options failed", err);
-                throw err;
-            }
-
-            getFilter(); // Now get the filter and start syncing
-        };
-
-        const getFilter = async () => {
-            debuglog("Getting filter...");
-            let filter;
-            if (this.opts.filter) {
-                filter = this.opts.filter;
-            } else {
-                filter = buildDefaultFilter();
-            }
-
-            let filterId;
-            try {
-                filterId = await client.getOrCreateFilter(getFilterName(client.credentials.userId), filter);
-            } catch (err) {
-                logger.error("Getting filter failed", err);
-                if (this.shouldAbortSync(err)) return;
-                // wait for saved sync to complete before doing anything else,
-                // otherwise the sync state will end up being incorrect
-                debuglog("Waiting for saved sync before retrying filter...");
-                await this.recoverFromSyncStartupError(savedSyncPromise, err);
-                getFilter();
-                return;
-            }
-            // reset the notifications timeline to prepare it to paginate from
-            // the current point in time.
-            // The right solution would be to tie /sync pagination tokens into
-            // /notifications API somehow.
-            client.resetNotifTimelineSet();
-
-            if (this.currentSyncRequest === null) {
-                // Send this first sync request here so we can then wait for the saved
-                // sync data to finish processing before we process the results of this one.
+            if (savedSyncToken) {
                debuglog("Sending first sync request...");
-                this.currentSyncRequest = this.doSyncRequest({ filterId }, savedSyncToken);
+            } else {
+                debuglog("Sending initial sync request...");
+                const initialFilter = this.buildDefaultFilter();
+                initialFilter.setDefinition(filter.getDefinition());
+                initialFilter.setTimelineLimit(this.opts.initialSyncLimit);
+                // Use an inline filter, no point uploading it for a single usage
+                firstSyncFilter = JSON.stringify(initialFilter.getDefinition());
            }

-            // Now wait for the saved sync to finish...
-            debuglog("Waiting for saved sync before starting sync processing...");
-            await savedSyncPromise;
-            this.doSync({ filterId });
-        };
-
-        if (client.isGuest()) {
-            // no push rules for guests, no access to POST filter for guests.
-            this.doSync({});
-        } else {
-            // Pull the saved sync token out first, before the worker starts sending
-            // all the sync data which could take a while. This will let us send our
-            // first incremental sync request before we've processed our saved data.
-            debuglog("Getting saved sync token...");
-            savedSyncPromise = client.store.getSavedSyncToken().then((tok) => {
-                debuglog("Got saved sync token");
-                savedSyncToken = tok;
-                debuglog("Getting saved sync...");
-                return client.store.getSavedSync();
-            }).then((savedSync) => {
-                debuglog(`Got reply from saved sync, exists? ${!!savedSync}`);
-                if (savedSync) {
-                    return this.syncFromCache(savedSync);
-                }
-            }).catch(err => {
-                logger.error("Getting saved sync failed", err);
-            });
-            // Now start the first incremental sync request: this can also
-            // take a while so if we set it going now, we can wait for it
-            // to finish while we process our saved sync data.
-            getPushRules();
+            // Send this first sync request here so we can then wait for the saved
+            // sync data to finish processing before we process the results of this one.
+            this.currentSyncRequest = this.doSyncRequest({ filter: firstSyncFilter }, savedSyncToken);
        }
+
+        // Now wait for the saved sync to finish...
+        debuglog("Waiting for saved sync before starting sync processing...");
+        await this.savedSyncPromise;
+        // process the first sync request and continue syncing with the normal filterId
+        return this.doSync({ filter: filterId });
    }

    /**
@@ -791,9 +730,7 @@ export class SyncApi {
        // global.window AND global.window.removeEventListener.
        // Some platforms (e.g. React Native) register global.window,
        // but do not have global.window.removeEventListener.
-        if (global.window && global.window.removeEventListener) {
-            global.window.removeEventListener("online", this.onOnline, false);
-        }
+        global.window?.removeEventListener?.("online", this.onOnline, false);
        this.running = false;
        this.currentSyncRequest?.abort();
        if (this.keepAliveTimer) {
@@ -828,8 +765,7 @@ export class SyncApi {
        this.client.store.setSyncToken(nextSyncToken);

        // No previous sync, set old token to null
-        const syncEventData = {
-            oldSyncToken: null,
+        const syncEventData: ISyncStateData = {
            nextSyncToken,
            catchingUp: false,
            fromCache: true,
@@ -864,7 +800,91 @@ export class SyncApi {
     * @param {boolean} syncOptions.hasSyncedBefore
     */
    private async doSync(syncOptions: ISyncOptions): Promise<void> {
-        const client = this.client;
+        while (this.running) {
+            const syncToken = this.client.store.getSyncToken();
+
+            let data: ISyncResponse;
+            try {
+                //debuglog('Starting sync since=' + syncToken);
+                if (this.currentSyncRequest === null) {
+                    this.currentSyncRequest = this.doSyncRequest(syncOptions, syncToken);
+                }
+                data = await this.currentSyncRequest;
+            } catch (e) {
+                const abort = await this.onSyncError(e);
+                if (abort) return;
+                continue;
+            } finally {
+                this.currentSyncRequest = null;
+            }
+
+            //debuglog('Completed sync, next_batch=' + data.next_batch);
+
+            // set the sync token NOW *before* processing the events. We do this so
+            // if something barfs on an event we can skip it rather than constantly
+            // polling with the same token.
+            this.client.store.setSyncToken(data.next_batch);
+
+            // Reset after a successful sync
+            this.failedSyncCount = 0;
+
+            await this.client.store.setSyncData(data);
+
+            const syncEventData = {
+                oldSyncToken: syncToken,
+                nextSyncToken: data.next_batch,
+                catchingUp: this.catchingUp,
+            };
+
+            if (this.opts.crypto) {
+                // tell the crypto module we're about to process a sync
+                // response
+                await this.opts.crypto.onSyncWillProcess(syncEventData);
+            }
+
+            try {
+                await this.processSyncResponse(syncEventData, data);
+            } catch (e) {
+                // log the exception with stack if we have it, else fall back
+                // to the plain description
+                logger.error("Caught /sync error", e);
+
+                // Emit the exception for client handling
+                this.client.emit(ClientEvent.SyncUnexpectedError, e);
+            }
+
+            // update this as it may have changed
+            syncEventData.catchingUp = this.catchingUp;
+
+            // emit synced events
+            if (!syncOptions.hasSyncedBefore) {
+                this.updateSyncState(SyncState.Prepared, syncEventData);
+                syncOptions.hasSyncedBefore = true;
+            }
+
+            // tell the crypto module to do its processing. It may block (to do a
+            // /keys/changes request).
+            if (this.opts.crypto) {
+                await this.opts.crypto.onSyncCompleted(syncEventData);
+            }
+
+            // keep emitting SYNCING -> SYNCING for clients who want to do bulk updates
+            this.updateSyncState(SyncState.Syncing, syncEventData);
+
+            if (this.client.store.wantsSave()) {
+                // We always save the device list (if it's dirty) before saving the sync data:
+                // this means we know the saved device list data is at least as fresh as the
+                // stored sync data which means we don't have to worry that we may have missed
+                // device changes. We can also skip the delay since we're not calling this very
+                // frequently (and we don't really want to delay the sync for it).
+                if (this.opts.crypto) {
+                    await this.opts.crypto.saveDeviceList(0);
+                }
+
+                // tell databases that everything is now in a consistent state and can be saved.
+                this.client.store.save();
+            }
+        }

        if (!this.running) {
            debuglog("Sync no longer running: exiting.");
@@ -873,94 +893,7 @@ export class SyncApi {
                this.connectionReturnedDefer = null;
            }
            this.updateSyncState(SyncState.Stopped);
-            return;
        }
-
-        const syncToken = client.store.getSyncToken();
-
-        let data;
-        try {
-            //debuglog('Starting sync since=' + syncToken);
-            if (this.currentSyncRequest === null) {
-                this.currentSyncRequest = this.doSyncRequest(syncOptions, syncToken);
-            }
-            data = await this.currentSyncRequest;
-        } catch (e) {
-            this.onSyncError(e, syncOptions);
-            return;
-        } finally {
-            this.currentSyncRequest = null;
-        }
-
-        //debuglog('Completed sync, next_batch=' + data.next_batch);
-
-        // set the sync token NOW *before* processing the events. We do this so
-        // if something barfs on an event we can skip it rather than constantly
-        // polling with the same token.
-        client.store.setSyncToken(data.next_batch);
-
-        // Reset after a successful sync
-        this.failedSyncCount = 0;
-
-        await client.store.setSyncData(data);
-
-        const syncEventData = {
-            oldSyncToken: syncToken,
-            nextSyncToken: data.next_batch,
-            catchingUp: this.catchingUp,
-        };
-
-        if (this.opts.crypto) {
-            // tell the crypto module we're about to process a sync
-            // response
-            await this.opts.crypto.onSyncWillProcess(syncEventData);
-        }
-
-        try {
-            await this.processSyncResponse(syncEventData, data);
-        } catch (e) {
-            // log the exception with stack if we have it, else fall back
-            // to the plain description
-            logger.error("Caught /sync error", e);
-
-            // Emit the exception for client handling
-            this.client.emit(ClientEvent.SyncUnexpectedError, e);
-        }
-
-        // update this as it may have changed
-        syncEventData.catchingUp = this.catchingUp;
-
-        // emit synced events
-        if (!syncOptions.hasSyncedBefore) {
-            this.updateSyncState(SyncState.Prepared, syncEventData);
-            syncOptions.hasSyncedBefore = true;
-        }
-
-        // tell the crypto module to do its processing. It may block (to do a
-        // /keys/changes request).
-        if (this.opts.crypto) {
-            await this.opts.crypto.onSyncCompleted(syncEventData);
-        }
-
-        // keep emitting SYNCING -> SYNCING for clients who want to do bulk updates
-        this.updateSyncState(SyncState.Syncing, syncEventData);
-
-        if (client.store.wantsSave()) {
-            // We always save the device list (if it's dirty) before saving the sync data:
-            // this means we know the saved device list data is at least as fresh as the
-            // stored sync data which means we don't have to worry that we may have missed
-            // device changes. We can also skip the delay since we're not calling this very
-            // frequently (and we don't really want to delay the sync for it).
-            if (this.opts.crypto) {
-                await this.opts.crypto.saveDeviceList(0);
-            }
-
-            // tell databases that everything is now in a consistent state and can be saved.
-            client.store.save();
-        }
-
-        // Begin next sync
-        this.doSync(syncOptions);
    }

    private doSyncRequest(syncOptions: ISyncOptions, syncToken: string): IAbortablePromise<ISyncResponse> {
@@ -974,7 +907,7 @@ export class SyncApi {
    private getSyncParams(syncOptions: ISyncOptions, syncToken: string): ISyncParams {
        let pollTimeout = this.opts.pollTimeout;

-        if (this.getSyncState() !== 'SYNCING' || this.catchingUp) {
+        if (this.getSyncState() !== SyncState.Syncing || this.catchingUp) {
            // unless we are happily syncing already, we want the server to return
            // as quickly as possible, even if there are no events queued. This
            // serves two purposes:
@@ -990,13 +923,13 @@ export class SyncApi {
            pollTimeout = 0;
        }

-        let filterId = syncOptions.filterId;
-        if (this.client.isGuest() && !filterId) {
-            filterId = this.getGuestFilter();
+        let filter = syncOptions.filter;
+        if (this.client.isGuest() && !filter) {
+            filter = this.getGuestFilter();
        }

        const qps: ISyncParams = {
-            filter: filterId,
+            filter,
            timeout: pollTimeout,
        };

@@ -1013,7 +946,7 @@ export class SyncApi {
            qps._cacheBuster = Date.now();
        }

-        if (this.getSyncState() == 'ERROR' || this.getSyncState() == 'RECONNECTING') {
+        if ([SyncState.Reconnecting, SyncState.Error].includes(this.getSyncState())) {
            // we think the connection is dead. If it comes back up, we won't know
            // about it till /sync returns. If the timeout= is high, this could
            // be a long time. Set it to 0 when doing retries so we don't have to wait
@@ -1024,7 +957,7 @@ export class SyncApi {
        return qps;
    }

-    private onSyncError(err: MatrixError, syncOptions: ISyncOptions): void {
+    private async onSyncError(err: MatrixError): Promise<boolean> {
        if (!this.running) {
            debuglog("Sync no longer running: exiting");
            if (this.connectionReturnedDefer) {
@@ -1032,14 +965,13 @@ export class SyncApi {
                this.connectionReturnedDefer = null;
            }
            this.updateSyncState(SyncState.Stopped);
-            return;
+            return true; // abort
        }

        logger.error("/sync error %s", err);
-        logger.error(err);

        if (this.shouldAbortSync(err)) {
-            return;
+            return true; // abort
        }

        this.failedSyncCount++;
@@ -1053,20 +985,7 @@ export class SyncApi {
        // erroneous. We set the state to 'reconnecting'
        // instead, so that clients can observe this state
        // if they wish.
-        this.startKeepAlives().then((connDidFail) => {
-            // Only emit CATCHUP if we detected a connectivity error: if we didn't,
-            // it's quite likely the sync will fail again for the same reason and we
-            // want to stay in ERROR rather than keep flip-flopping between ERROR
-            // and CATCHUP.
-            if (connDidFail && this.getSyncState() === SyncState.Error) {
-                this.updateSyncState(SyncState.Catchup, {
-                    oldSyncToken: null,
-                    nextSyncToken: null,
-                    catchingUp: true,
-                });
-            }
-            this.doSync(syncOptions);
-        });
+        const keepAlivePromise = this.startKeepAlives();

        this.currentSyncRequest = null;
        // Transition from RECONNECTING to ERROR after a given number of failed syncs
@@ -1075,6 +994,19 @@ export class SyncApi {
                SyncState.Error : SyncState.Reconnecting,
            { error: err },
        );
+
+        const connDidFail = await keepAlivePromise;
+
+        // Only emit CATCHUP if we detected a connectivity error: if we didn't,
+        // it's quite likely the sync will fail again for the same reason and we
+        // want to stay in ERROR rather than keep flip-flopping between ERROR
+        // and CATCHUP.
+        if (connDidFail && this.getSyncState() === SyncState.Error) {
+            this.updateSyncState(SyncState.Catchup, {
+                catchingUp: true,
+            });
+        }
+        return false;
    }

    /**
@@ -1133,7 +1065,7 @@ export class SyncApi {
        // - The isBrandNewRoom boilerplate is boilerplatey.

        // handle presence events (User objects)
-        if (data.presence && Array.isArray(data.presence.events)) {
+        if (Array.isArray(data.presence?.events)) {
            data.presence.events.map(client.getEventMapper()).forEach(
                function(presenceEvent) {
                    let user = client.store.getUser(presenceEvent.getSender());
@@ -1149,7 +1081,7 @@ export class SyncApi {
        }

        // handle non-room account_data
-        if (data.account_data && Array.isArray(data.account_data.events)) {
+        if (Array.isArray(data.account_data?.events)) {
            const events = data.account_data.events.map(client.getEventMapper());
            const prevEventsMap = events.reduce((m, c) => {
                m[c.getId()] = client.store.getAccountData(c.getType());
@@ -1290,8 +1222,7 @@ export class SyncApi {
                // bother setting it here. We trust our calculations better than the
                // server's for this case, and therefore will assume that our non-zero
                // count is accurate.
-                if (!encrypted
-                    || (encrypted && room.getUnreadNotificationCount(NotificationCountType.Highlight) <= 0)) {
+                if (!encrypted || room.getUnreadNotificationCount(NotificationCountType.Highlight) <= 0) {
                    room.setUnreadNotificationCount(
                        NotificationCountType.Highlight,
                        joinObj.unread_notifications.highlight_count,
@@ -1304,8 +1235,7 @@ export class SyncApi {
            if (joinObj.isBrandNewRoom) {
                // set the back-pagination token. Do this *before* adding any
                // events so that clients can start back-paginating.
-                room.getLiveTimeline().setPaginationToken(
-                    joinObj.timeline.prev_batch, EventTimeline.BACKWARDS);
+                room.getLiveTimeline().setPaginationToken(joinObj.timeline.prev_batch, EventTimeline.BACKWARDS);
            } else if (joinObj.timeline.limited) {
                let limited = true;

@@ -1792,3 +1722,49 @@ function createNewUser(client: MatrixClient, userId: string): User {
    return user;
 }

+// /!\ This function is not intended for public use! It's only exported from
+// here in order to share some common logic with sliding-sync-sdk.ts.
+export function _createAndReEmitRoom(client: MatrixClient, roomId: string, opts: Partial<IStoredClientOpts>): Room {
+    const { timelineSupport } = client;
+
+    const room = new Room(roomId, client, client.getUserId(), {
+        lazyLoadMembers: opts.lazyLoadMembers,
+        pendingEventOrdering: opts.pendingEventOrdering,
+        timelineSupport,
+    });
+
+    client.reEmitter.reEmit(room, [
+        RoomEvent.Name,
+        RoomEvent.Redaction,
+        RoomEvent.RedactionCancelled,
+        RoomEvent.Receipt,
+        RoomEvent.Tags,
+        RoomEvent.LocalEchoUpdated,
+        RoomEvent.AccountData,
+        RoomEvent.MyMembership,
+        RoomEvent.Timeline,
+        RoomEvent.TimelineReset,
+        RoomStateEvent.Events,
+        RoomStateEvent.Members,
+        RoomStateEvent.NewMember,
+        RoomStateEvent.Update,
+        BeaconEvent.New,
+        BeaconEvent.Update,
+        BeaconEvent.Destroy,
+        BeaconEvent.LivenessChange,
+    ]);
+
+    // We need to add a listener for RoomState.members in order to hook them
+    // correctly.
+    room.on(RoomStateEvent.NewMember, (event, state, member) => {
+        member.user = client.getUser(member.userId);
+        client.reEmitter.reEmit(member, [
+            RoomMemberEvent.Name,
+            RoomMemberEvent.Typing,
+            RoomMemberEvent.PowerLevel,
+            RoomMemberEvent.Membership,
+        ]);
+    });
+
+    return room;
+}
@@ -24,8 +24,33 @@ import unhomoglyph from "unhomoglyph";
 import promiseRetry from "p-retry";

 import type * as NodeCrypto from "crypto";
-import { MatrixEvent } from ".";
+import { MatrixClient, MatrixEvent } from ".";
 import { M_TIMESTAMP } from "./@types/location";
+import { ReceiptType } from "./@types/read_receipts";
+
+const interns = new Map<string, string>();
+
+/**
+ * Internalises a string, reusing a known pointer or storing the pointer
+ * if needed for future strings.
+ * @param str The string to internalise.
+ * @returns The internalised string.
+ */
+export function internaliseString(str: string): string {
+    // Unwrap strings before entering the map, if we somehow got a wrapped
+    // string as our input. This should only happen from tests.
+    if ((str as unknown) instanceof String) {
+        str = str.toString();
+    }
+
+    // Check the map to see if we can store the value
+    if (!interns.has(str)) {
+        interns.set(str, str);
+    }
+
+    // Return any cached string reference
+    return interns.get(str);
+}

 /**
 * Encode a dictionary of query parameters.
@@ -73,8 +98,7 @@ export function decodeParams(query: string): QueryDict {
 * variables with. E.g. { "$bar": "baz" }.
 * @return {string} The result of replacing all template variables e.g. '/foo/baz'.
 */
-export function encodeUri(pathTemplate: string,
-    variables: Record<string, string>): string {
+export function encodeUri(pathTemplate: string, variables: Record<string, string>): string {
    for (const key in variables) {
        if (!variables.hasOwnProperty(key)) {
            continue;
@@ -214,33 +238,24 @@ export function deepCompare(x: any, y: any): boolean {
            }
        }
    } else {
-        // disable jshint "The body of a for in should be wrapped in an if
-        // statement"
-        /* jshint -W089 */
-
        // check that all of y's direct keys are in x
-        let p;
-        for (p in y) {
+        for (const p in y) {
            if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
                return false;
            }
        }

        // finally, compare each of x's keys with y
-        for (p in y) { // eslint-disable-line guard-for-in
-            if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
-                return false;
-            }
-            if (!deepCompare(x[p], y[p])) {
+        for (const p in x) {
+            if (y.hasOwnProperty(p) !== x.hasOwnProperty(p) || !deepCompare(x[p], y[p])) {
                return false;
            }
        }
    }
-    /* jshint +W089 */
    return true;
 }

-// Dev note: This returns a tuple, but jsdoc doesn't like that. https://github.com/jsdoc/jsdoc/issues/1703
+// Dev note: This returns an array of tuples, but jsdoc doesn't like that. https://github.com/jsdoc/jsdoc/issues/1703
 /**
 * Creates an array of object properties/values (entries) then
 * sorts the result by key, recursively. The input object must
@@ -327,22 +342,28 @@ export function escapeRegExp(string: string): string {
 }

 export function globToRegexp(glob: string, extended?: any): string {
-    extended = typeof(extended) === 'boolean' ? extended : true;
    // From
    // https://github.com/matrix-org/synapse/blob/abbee6b29be80a77e05730707602f3bbfc3f38cb/synapse/push/__init__.py#L132
    // Because micromatch is about 130KB with dependencies,
    // and minimatch is not much better.
-    let pat = escapeRegExp(glob);
-    pat = pat.replace(/\\\*/g, '.*');
-    pat = pat.replace(/\?/g, '.');
-    if (extended) {
-        pat = pat.replace(/\\\[(!|)(.*)\\]/g, function(match, p1, p2, offset, string) {
-            const first = p1 && '^' || '';
-            const second = p2.replace(/\\-/, '-');
-            return '[' + first + second + ']';
-        });
-    }
-    return pat;
+    const replacements: ([RegExp, string | ((substring: string, ...args: any[]) => string) ])[] = [
+        [/\\\*/g, '.*'],
+        [/\?/g, '.'],
+        extended !== false && [
+            /\\\[(!|)(.*)\\]/g,
+            (_match: string, neg: string, pat: string) => [
+                '[',
+                neg ? '^' : '',
+                pat.replace(/\\-/, '-'),
+                ']',
+            ].join(''),
+        ],
+    ];
+    return replacements.reduce(
+        // https://github.com/microsoft/TypeScript/issues/30134
+        (pat, args) => args ? pat.replace(args[0], args[1] as any) : pat,
+        escapeRegExp(glob),
+    );
 }

 export function ensureNoTrailingSlash(url: string): string {
@@ -648,3 +669,18 @@ function getContentTimestampWithFallback(event: MatrixEvent): number {
 export function sortEventsByLatestContentTimestamp(left: MatrixEvent, right: MatrixEvent): number {
    return getContentTimestampWithFallback(right) - getContentTimestampWithFallback(left);
 }
+
+export async function getPrivateReadReceiptField(client: MatrixClient): Promise<ReceiptType | null> {
+    if (await client.doesServerSupportUnstableFeature("org.matrix.msc2285.stable")) return ReceiptType.ReadPrivate;
+    if (await client.doesServerSupportUnstableFeature("org.matrix.msc2285")) return ReceiptType.UnstableReadPrivate;
+    return null;
+}
+
+export function isSupportedReceiptType(receiptType: string): boolean {
+    return [
+        ReceiptType.Read,
+        ReceiptType.ReadPrivate,
+        ReceiptType.UnstableReadPrivate,
+    ].includes(receiptType as ReceiptType);
+}
+
@@ -523,24 +523,22 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
            return;
        }

-        // Try to find a feed with the same purpose as the new stream,
-        // if we find it replace the old stream with the new one
-        const existingFeed = this.getRemoteFeeds().find((feed) => feed.purpose === purpose);
-        if (existingFeed) {
-            existingFeed.setNewStream(stream);
-        } else {
-            this.feeds.push(new CallFeed({
-                client: this.client,
-                roomId: this.roomId,
-                userId,
-                stream,
-                purpose,
-                audioMuted,
-                videoMuted,
-            }));
-            this.emit(CallEvent.FeedsChanged, this.feeds);
+        if (this.getFeedByStreamId(stream.id)) {
+            logger.warn(`Ignoring stream with id ${stream.id} because we already have a feed for it`);
+            return;
        }

+        this.feeds.push(new CallFeed({
+            client: this.client,
+            roomId: this.roomId,
+            userId,
+            stream,
+            purpose,
+            audioMuted,
+            videoMuted,
+        }));
+        this.emit(CallEvent.FeedsChanged, this.feeds);
+
        logger.info(`Pushed remote stream (id="${stream.id}", active="${stream.active}", purpose=${purpose})`);
    }

@@ -562,24 +560,22 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
            return;
        }

-        // Try to find a feed with the same stream id as the new stream,
-        // if we find it replace the old stream with the new one
-        const feed = this.getFeedByStreamId(stream.id);
-        if (feed) {
-            feed.setNewStream(stream);
-        } else {
-            this.feeds.push(new CallFeed({
-                client: this.client,
-                roomId: this.roomId,
-                audioMuted: false,
-                videoMuted: false,
-                userId,
-                stream,
-                purpose,
-            }));
-            this.emit(CallEvent.FeedsChanged, this.feeds);
+        if (this.getFeedByStreamId(stream.id)) {
+            logger.warn(`Ignoring stream with id ${stream.id} because we already have a feed for it`);
+            return;
        }

+        this.feeds.push(new CallFeed({
+            client: this.client,
+            roomId: this.roomId,
+            audioMuted: false,
+            videoMuted: false,
+            userId,
+            stream,
+            purpose,
+        }));
+        this.emit(CallEvent.FeedsChanged, this.feeds);
+
        logger.info(`Pushed remote stream (id="${stream.id}", active="${stream.active}")`);
    }

@@ -592,25 +588,23 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
        setTracksEnabled(stream.getAudioTracks(), true);
        setTracksEnabled(stream.getVideoTracks(), true);

-        // We try to replace an existing feed if there already is one with the same purpose
-        const existingFeed = this.getLocalFeeds().find((feed) => feed.purpose === purpose);
-        if (existingFeed) {
-            existingFeed.setNewStream(stream);
-        } else {
-            this.pushLocalFeed(
-                new CallFeed({
-                    client: this.client,
-                    roomId: this.roomId,
-                    audioMuted: false,
-                    videoMuted: false,
-                    userId,
-                    stream,
-                    purpose,
-                }),
-                addToPeerConnection,
-            );
-            this.emit(CallEvent.FeedsChanged, this.feeds);
+        if (this.getFeedByStreamId(stream.id)) {
+            logger.warn(`Ignoring stream with id ${stream.id} because we already have a feed for it`);
+            return;
        }
+
+        this.pushLocalFeed(
+            new CallFeed({
+                client: this.client,
+                roomId: this.roomId,
+                audioMuted: false,
+                videoMuted: false,
+                userId,
+                stream,
+                purpose,
+            }),
+            addToPeerConnection,
+        );
    }

    /**
@@ -872,8 +866,6 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
    public answerWithCallFeeds(callFeeds: CallFeed[]): void {
        if (this.inviteOrAnswerSent) return;

-        logger.debug(`Answering call ${this.callId}`);
-
        this.gotCallFeedsForAnswer(callFeeds);
    }

@@ -1142,7 +1134,7 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
            await this.upgradeCall(false, true);
            return this.isLocalVideoMuted();
        }
-        this.localUsermediaFeed?.setVideoMuted(muted);
+        this.localUsermediaFeed?.setAudioVideoMuted(null, muted);
        this.updateMuteStatus();
        return this.isLocalVideoMuted();
    }
@@ -1174,7 +1166,7 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
            await this.upgradeCall(true, false);
            return this.isMicrophoneMuted();
        }
-        this.localUsermediaFeed?.setAudioMuted(muted);
+        this.localUsermediaFeed?.setAudioVideoMuted(muted, null);
        this.updateMuteStatus();
        return this.isMicrophoneMuted();
    }
@@ -1585,8 +1577,9 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
        this.remoteSDPStreamMetadata = utils.recursivelyAssign(this.remoteSDPStreamMetadata || {}, metadata, true);
        for (const feed of this.getRemoteFeeds()) {
            const streamId = feed.stream.id;
-            feed.setAudioMuted(this.remoteSDPStreamMetadata[streamId]?.audio_muted);
-            feed.setVideoMuted(this.remoteSDPStreamMetadata[streamId]?.video_muted);
+            const metadata = this.remoteSDPStreamMetadata[streamId];
+
+            feed.setAudioVideoMuted(metadata?.audio_muted, metadata?.video_muted);
            feed.purpose = this.remoteSDPStreamMetadata[streamId]?.purpose;
        }
    }
@@ -1870,10 +1863,10 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
        const shouldTerminate = (
            // reject events also end the call if it's ringing: it's another of
            // our devices rejecting the call.
-            ([CallState.InviteSent, CallState.Ringing].includes(this.state)) ||
+            [CallState.InviteSent, CallState.Ringing].includes(this.state) ||
            // also if we're in the init state and it's an inbound call, since
            // this means we just haven't entered the ringing state yet
-            this.state === CallState.Fledgling && this.direction === CallDirection.Inbound
+            (this.state === CallState.Fledgling && this.direction === CallDirection.Inbound)
        );

        if (shouldTerminate) {
@@ -175,30 +175,18 @@ export class CallFeed extends TypedEventEmitter<CallFeedEvent, EventHandlerMap>
    }

    /**
-     * Replaces the current MediaStream with a new one.
-     * This method should be only used by MatrixCall.
-     * @param newStream new stream with which to replace the current one
-     */
-    public setNewStream(newStream: MediaStream): void {
-        this.updateStream(this.stream, newStream);
-    }
-
-    /**
-     * Set feed's internal audio mute state
-     * @param muted is the feed's audio muted?
-     */
-    public setAudioMuted(muted: boolean): void {
-        this.audioMuted = muted;
-        this.speakingVolumeSamples.fill(-Infinity);
-        this.emit(CallFeedEvent.MuteStateChanged, this.audioMuted, this.videoMuted);
-    }
-
-    /**
-     * Set feed's internal video mute state
+     * Set one or both of feed's internal audio and video video mute state
+     * Either value may be null to leave it as-is
     * @param muted is the feed's video muted?
     */
-    public setVideoMuted(muted: boolean): void {
-        this.videoMuted = muted;
+    public setAudioVideoMuted(audioMuted: boolean, videoMuted: boolean): void {
+        if (audioMuted !== null) {
+            if (this.audioMuted !== audioMuted) {
+                this.speakingVolumeSamples.fill(-Infinity);
+            }
+            this.audioMuted = audioMuted;
+        }
+        if (videoMuted !== null) this.videoMuted = videoMuted;
        this.emit(CallFeedEvent.MuteStateChanged, this.audioMuted, this.videoMuted);
    }

@@ -12,6 +12,6 @@
  },
  "include": [
    "./src/**/*.ts",
-    "./spec/**/*.ts",
+    "./spec/**/*.ts"
  ]
 }