Support Matrix v1.14

Checklist taken from https://spec.matrix.org/v1.14/changelog/v1.14/checklist.md

Follows: #18118 (v1.12, v1.13)

---

# Extra items (stub)

- [ ] https://github.com/element-hq/synapse/issues/20116

# Matrix Specification v1.14 Changelog

| | |
|---|---|
| Git commit | https://github.com/matrix-org/matrix-spec/tree/v1.14 |
| Release date | March 27, 2025 |

## Client-Server API

**New Endpoints**

- [x] Add `POST /_matrix/client/v3/users/{userId}/report`, as per [MSC4260](https://github.com/matrix-org/matrix-spec-proposals/pull/4260). ([#2093](https://github.com/matrix-org/matrix-spec/issues/2093))

**Removed Endpoints**

- [x] Remove `server_name` parameter from `/_matrix/client/v3/join/{roomIdOrAlias}` and `/_matrix/client/v3/knock/{roomIdOrAlias}`, as per [MSC4213](https://github.com/matrix-org/matrix-spec-proposals/pull/4213). ([#2059](https://github.com/matrix-org/matrix-spec/issues/2059))

**Spec Clarifications**

- [x] The `POST /_matrix/client/v3/rooms/{roomId}/initialSync` endpoint is no longer deprecated, as it is still used for peeking. ([#2036](https://github.com/matrix-org/matrix-spec/issues/2036))
- [x] Clarify wording in the `/join` endpoints' summaries and descriptions. Contributed by @HarHarLinks. ([#2038](https://github.com/matrix-org/matrix-spec/issues/2038))
- [x] Clarify formats of string types. ([#2046](https://github.com/matrix-org/matrix-spec/issues/2046))
- [x] Fix various typos throughout the specification. ([#2047](https://github.com/matrix-org/matrix-spec/issues/2047), [#2048](https://github.com/matrix-org/matrix-spec/issues/2048), [#2080](https://github.com/matrix-org/matrix-spec/issues/2080), [#2091](https://github.com/matrix-org/matrix-spec/issues/2091))
- [x] Document the `instance_id` field of `Protocol Instance` in the responses to `GET /_matrix/client/v3/thirdparty/protocols` and `GET /_matrix/client/v3/thirdparty/protocol/{protocol}`. ([#2051](https://github.com/matrix-org/matrix-spec/issues/2051))
- [x] Applying redactions is a SHOULD for clients. ([#2055](https://github.com/matrix-org/matrix-spec/issues/2055))
- [x] Clarify which rooms are returned from `/hierarchy`. ([#2064](https://github.com/matrix-org/matrix-spec/issues/2064))
- [x] Clients can choose which history visibility options they offer to users when creating rooms. ([#2072](https://github.com/matrix-org/matrix-spec/issues/2072))

## Server-Server API

**Spec Clarifications**

- [x] Remove the `origin` field in `PUT /send_join` responses, because it was never sent in the first place. ([#2050](https://github.com/matrix-org/matrix-spec/issues/2050))
- [x] Clarify that `m.join_rules` should be in the `auth_events` of an `m.room.member` event with a `membership` of `knock`. ([#2063](https://github.com/matrix-org/matrix-spec/issues/2063))
- [x] Remove an erroneous `room_id` field in a few examples. ([#2076](https://github.com/matrix-org/matrix-spec/issues/2076))

## Application Service API

No significant changes.

## Identity Service API

No significant changes.

## Push Gateway API

No significant changes.

## Room Versions

**Backwards Compatible Changes**

- [x] Update the default room version to 11, as per [MSC4239](https://github.com/matrix-org/matrix-spec-proposals/pull/4239). ([#2105](https://github.com/matrix-org/matrix-spec/issues/2105)) — #18530 : https://github.com/element-hq/synapse/pull/18680

**Spec Clarifications**

- [x] For room versions 6 and 7, clarify in the authorization rules that `m.federate` must be checked and that events with rejected auth events must be rejected, for parity with all the other room versions. ([#2065](https://github.com/matrix-org/matrix-spec/issues/2065))
- [x] Fix various typos throughout the specification. ([#2066](https://github.com/matrix-org/matrix-spec/issues/2066))
- [x] Refactor PDU definitions to reduce duplication. ([#2070](https://github.com/matrix-org/matrix-spec/issues/2070))
- [x] Clarify the maximum `depth` value for room versions 6, 7, 8, 9, 10, and 11. ([#2114](https://github.com/matrix-org/matrix-spec/issues/2114))

## Appendices

**Spec Clarifications**

- [x] Clarify that arbitrary unicode is allowed in user/room IDs and room aliases. ([#1506](https://github.com/matrix-org/matrix-spec/issues/1506))

## Internal Changes/Tooling

**Spec Clarifications**

- [x] Generate the changelog release info with Hugo, rather than the changelog generation script. ([#2033](https://github.com/matrix-org/matrix-spec/issues/2033))
- [x] Update release steps documentation. ([#2041](https://github.com/matrix-org/matrix-spec/issues/2041))
- [x] Remove unused `release_date` from Hugo config. ([#2042](https://github.com/matrix-org/matrix-spec/issues/2042))
- [x] Clarify that v1.0 of Matrix was a release prior to the current global versioning system. ([#2045](https://github.com/matrix-org/matrix-spec/issues/2045))
- [x] Fix syntax highlighting and click-to-copy buttons for code blocks by purging less CSS. ([#2049](https://github.com/matrix-org/matrix-spec/issues/2049))
- [x] Fix the version of the Identity Service API when Matrix 1.0 was introduced. ([#2061](https://github.com/matrix-org/matrix-spec/issues/2061))
- [x] Fix parsing of nested slices in `resolve-refs` and `resolve-allof` partials. ([#2069](https://github.com/matrix-org/matrix-spec/issues/2069))
- [x] Deduplicate the definition of `RoomKeysUpdateResponse`. ([#2073](https://github.com/matrix-org/matrix-spec/issues/2073))
- [x] Deduplicate the definitions of `Invite3pid`. ([#2074](https://github.com/matrix-org/matrix-spec/issues/2074))
- [x] Support more locations for examples in OpenAPI definitions and JSON schemas. ([#2076](https://github.com/matrix-org/matrix-spec/issues/2076))
- [x] Add link to the git commit for the unstable changelog. ([#2078](https://github.com/matrix-org/matrix-spec/issues/2078))