- Allow `/versions` to optionally accept authentication, as per [MSC4026](https://github.com/matrix-org/matrix-spec-proposals/pull/4026). ([#1728](https://github.com/matrix-org/matrix-spec/issues/1728))
- Add local erasure requests, as per [MSC4025](https://github.com/matrix-org/matrix-spec-proposals/pull/4025). ([#1730](https://github.com/matrix-org/matrix-spec/issues/1730))
- Use the `body` field as optional media caption, as per [MSC2530](https://github.com/matrix-org/matrix-spec-proposals/pull/2530). ([#1731](https://github.com/matrix-org/matrix-spec/issues/1731))
- Add server support discovery endpoint, as per [MSC1929](https://github.com/matrix-org/matrix-spec-proposals/pull/1929). ([#1733](https://github.com/matrix-org/matrix-spec/issues/1733))
- Add support for multi-stream VoIP, as per [MSC3077](https://github.com/matrix-org/matrix-spec-proposals/pull/3077). ([#1735](https://github.com/matrix-org/matrix-spec/issues/1735))
- Specify that the `Retry-After` header may be used to rate-limit a client, as per [MSC4041](https://github.com/matrix-org/matrix-spec-proposals/pull/4041). ([#1737](https://github.com/matrix-org/matrix-spec/issues/1737))
- Add support for recursion on the `GET /relations` endpoints, as per [MSC3981](https://github.com/matrix-org/matrix-spec-proposals/pull/3981). ([#1746](https://github.com/matrix-org/matrix-spec/issues/1746))
**Spec Clarifications**
- The [strike](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/strike) element is deprecated in the HTML spec. Clients should prefer [s](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/s) instead. ([#1629](https://github.com/matrix-org/matrix-spec/issues/1629))
- Clarify that read receipts should be batched by thread as well as by room. ([#1685](https://github.com/matrix-org/matrix-spec/issues/1685))
- Clarify that threads can be created based on replies. ([#1687](https://github.com/matrix-org/matrix-spec/issues/1687))
- Clarify in the reply fallbacks example that the prefix sequence should be repeated for each line. ([#1690](https://github.com/matrix-org/matrix-spec/issues/1690))
- Clarify the format of account data objects for secret storage. ([#1695](https://github.com/matrix-org/matrix-spec/issues/1695), [#1734](https://github.com/matrix-org/matrix-spec/issues/1734))
- Clarify that the key backup MAC is implemented incorrectly and does not pass the ciphertext through HMAC-SHA-256. ([#1712](https://github.com/matrix-org/matrix-spec/issues/1712))
- Clarify one-time key and fallback key types in examples. ([#1715](https://github.com/matrix-org/matrix-spec/issues/1715))
- Clarify that the HKDF calculation for SAS uses base64-encoded keys rather than the raw key bytes. ([#1719](https://github.com/matrix-org/matrix-spec/issues/1719))
- Clarify how to perform the ECDH exchange in step 12 of the SAS process. ([#1720](https://github.com/matrix-org/matrix-spec/issues/1720))
- Document the deprecation policy of HTML tags, as per [MSC4077](https://github.com/matrix-org/matrix-spec-proposals/pull/4077). ([#1732](https://github.com/matrix-org/matrix-spec/issues/1732))
- The [font](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/font) element is deprecated in the HTML spec. Clients should prefer [span](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/span) with the `data-mx-bg-color` and `data-mx-color` attributes instead. ([#1739](https://github.com/matrix-org/matrix-spec/issues/1739))
- Disambiguate uses of `PublicRoomsChunk` in the `GET /hierarchy` endpoint. ([#1740](https://github.com/matrix-org/matrix-spec/issues/1740))
- Clarify that `sdpMid` and `sdpMLineIndex` are not required in `m.call.candidates`. ([#1742](https://github.com/matrix-org/matrix-spec/issues/1742))
- Fix various typos throughout the specification. ([#1748](https://github.com/matrix-org/matrix-spec/issues/1748))
- Clearly indicate that each `Content-Type` may have distinct behaviour on non-JSON requests/responses. ([#1756](https://github.com/matrix-org/matrix-spec/issues/1756))
- Clarify that the `m.push_rules` account data type cannot be set using the `/account_data` API, as per [MSC4010](https://github.com/matrix-org/matrix-spec-proposals/pull/4010). ([#1763](https://github.com/matrix-org/matrix-spec/issues/1763))
- Clarify Server-Server API request signing example by using the `POST` HTTP method, as `GET` requests don't have request bodies. ([#1721](https://github.com/matrix-org/matrix-spec/issues/1721))
- Disambiguate uses of `PublicRoomsChunk` in the `GET /hierarchy` endpoint. ([#1740](https://github.com/matrix-org/matrix-spec/issues/1740))
- Clarify that the `children_state`, `room_type` and `allowed_room_ids` properties in the items of the `children` array of the response of the `GET /hierarchy` endpoint are not required. ([#1741](https://github.com/matrix-org/matrix-spec/issues/1741))
- Clarify that the `/login` and `/register` endpoints should fail when using the `m.login.application_service` login type without a valid `as_token`. ([#1744](https://github.com/matrix-org/matrix-spec/issues/1744))
- For room versions 7 through 11: Clarify that `invite->knock` is not a legal transition. ([#1717](https://github.com/matrix-org/matrix-spec/issues/1717))
- Update the spec release process. ([#1680](https://github.com/matrix-org/matrix-spec/issues/1680))
- Minor clarifications to the contributing guide. ([#1697](https://github.com/matrix-org/matrix-spec/issues/1697))
- Update Docsy to v0.8.0. ([#1699](https://github.com/matrix-org/matrix-spec/issues/1699), [#1762](https://github.com/matrix-org/matrix-spec/issues/1762))
- Fix npm release script for `@matrix-org/spec`. ([#1713](https://github.com/matrix-org/matrix-spec/issues/1713))
- Add some clarifications around implementation requirements for MSCs. ([#1718](https://github.com/matrix-org/matrix-spec/issues/1718))
- Update HTML templates to include links to object schema definitions. ([#1724](https://github.com/matrix-org/matrix-spec/issues/1724))
- Factor out all the common parameters of the various `/relations` apis. ([#1745](https://github.com/matrix-org/matrix-spec/issues/1745))
- Add support for `$ref` URIs containing fragments in OpenAPI definitions and JSON schemas. ([#1751](https://github.com/matrix-org/matrix-spec/issues/1751), [#1754](https://github.com/matrix-org/matrix-spec/issues/1754))