Blog post for spec v1.17

content/blog/2025/12/2025-12-17-matrix-v1.17-release.md

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+title = "Matrix v1.17 specification released"
+date = "2025-12-18T16:00:00Z"
+path = "/blog/2025/12/18/matrix-v1.17-release"
+
+[taxonomies]
+author = ["Richard van der Hoff"]
+category = ["Releases", "Spec"]
++++
+
+Hey all,
+
+At this year’s Matrix Conference [we said](https://www.youtube.com/watch?v=2y8qtRLgalQ&t=744s) we were aiming for this very spec release to be 2.0 proper. It looks like the MSCs still need a little bit more time to get over the line though, but they’re extremely close — one of the next few releases is expected to be Matrix 2.0.
+
+Today we’re releasing [Matrix 1.17](https://spec.matrix.org/v1.17) while the 2.0 MSCs continue to make forward progress. This release is smaller than some, with four MSCs merged, but as normal also includes a number of clarifications.
+
+[Improvements to the spec website](https://www.youtube.com/watch?v=3Axa0Kw3XPI?t=879) include a dropdown to get at old spec versions more easily, and an index of HTTP endpoints at the top of each page.
+
+This release of the spec also sees the incorporation of the specifications for the [Olm and Megolm cryptographic ratchets](https://spec.matrix.org/v1.17/olm-megolm). Olm and Megolm themselves haven’t changed, but we did want them to be on the spec site :)
+
+Thanks especially to Johannes and Kévin for continuing to improve the quality of the spec with features, clarifications, and MSC text!
+
+<!-- more -->
+
+## The full changelog
+
+### Client-Server API
+
+**Removed Endpoints**
+
+- Remove legacy mentions, as per [MSC4210](https://github.com/matrix-org/matrix-spec-proposals/issues/4210). ([#2186](https://github.com/matrix-org/matrix-spec/issues/2186))
+
+**Backwards Compatible Changes**
+
+- Allow application services to masquerade as specific devices belonging to users, as per [MSC4326](https://github.com/matrix-org/matrix-spec-proposals/pull/4326). ([#2221](https://github.com/matrix-org/matrix-spec/issues/2221))
+- Add the `m.oauth` authentication type for User-Interactive Authentication, as per [MSC4312](https://github.com/matrix-org/matrix-spec-proposals/pull/4312). ([#2234](https://github.com/matrix-org/matrix-spec/issues/2234))
+- Allow application services to manage devices and register users without the legacy authentication API, as per [MSC4190](https://github.com/matrix-org/matrix-spec-proposals/pull/4190). ([#2267](https://github.com/matrix-org/matrix-spec/issues/2267))
+
+**Spec Clarifications**
+
+- Push rule IDs are globally unique within their kind. ([#2214](https://github.com/matrix-org/matrix-spec/issues/2214))
+- Don't advertise `creator` field in description of room creation. ([#2215](https://github.com/matrix-org/matrix-spec/issues/2215))
+- `room_id` is required for peeking via `/_matrix/client/v3/events`. ([#2216](https://github.com/matrix-org/matrix-spec/issues/2216))
+- The `server-name` segment of MXC URIs is sanitised differently from the `media-id` segment. ([#2217](https://github.com/matrix-org/matrix-spec/issues/2217))
+- Add note to each endpoint that uses capability negotiation. ([#2223](https://github.com/matrix-org/matrix-spec/issues/2223))
+- Additional OpenGraph properties can be present in URL previews. ([#2225](https://github.com/matrix-org/matrix-spec/issues/2225))
+- Clarify the special casing of membership events and redactions in power levels. ([#2231](https://github.com/matrix-org/matrix-spec/issues/2231))
+- `M_RESOURCE_LIMIT_EXCEEDED` is now listed as a common error code. ([#2232](https://github.com/matrix-org/matrix-spec/issues/2232))
+- Add `m.login.terms` to enumeration of authentication types. ([#2233](https://github.com/matrix-org/matrix-spec/issues/2233))
+- Clarify how to use `state_after` ahead of declaring full support for its spec version. ([#2240](https://github.com/matrix-org/matrix-spec/issues/2240))
+- `device_one_time_keys_count` is only optional if no unclaimed one-time keys exist. ([#2245](https://github.com/matrix-org/matrix-spec/issues/2245))
+- Clarify that servers may choose not to use `M_USER_DEACTIVATED` at login time, for example for privacy reasons when they can't authenticate deactivated users. ([#2246](https://github.com/matrix-org/matrix-spec/issues/2246))
+- Usage of the `event_id_only` format for push notifications is not mandatory. ([#2255](https://github.com/matrix-org/matrix-spec/issues/2255))
+- Fix various typos throughout the specification. ([#2224](https://github.com/matrix-org/matrix-spec/issues/2224), [#2227](https://github.com/matrix-org/matrix-spec/issues/2227), [#2250](https://github.com/matrix-org/matrix-spec/issues/2250))
+
+
+### Server-Server API
+
+No significant changes.
+
+
+### Application Service API
+
+**Backwards Compatible Changes**
+
+- Allow application services to masquerade as specific devices belonging to users, as per [MSC4326](https://github.com/matrix-org/matrix-spec-proposals/pull/4326). ([#2221](https://github.com/matrix-org/matrix-spec/issues/2221))
+- Allow application services to manage devices and register users without the legacy authentication API, as per [MSC4190](https://github.com/matrix-org/matrix-spec-proposals/pull/4190). ([#2267](https://github.com/matrix-org/matrix-spec/issues/2267))
+
+**Spec Clarifications**
+
+- Fix JSON formatting in the "Server admin style permissions" examples. ([#2213](https://github.com/matrix-org/matrix-spec/issues/2213))
+
+
+### Identity Service API
+
+No significant changes.
+
+
+### Push Gateway API
+
+No significant changes.
+
+
+### Room Versions
+
+**Spec Clarifications**
+
+- In room versions 8 through 12, clarify that "sufficient permission to invite users" on restricted joins also includes being a joined member of the room. ([#2220](https://github.com/matrix-org/matrix-spec/issues/2220))
+- In room versions 3 through 12, clarify that when you have the power to redact, it is possible to redact events that you don't have the power to send. ([#2249](https://github.com/matrix-org/matrix-spec/issues/2249))
+
+
+### Appendices
+
+No significant changes.
+
+
+### Internal Changes/Tooling
+
+**Spec Clarifications**
+
+- Swapped icon for X (fka. twitter) to updated logo in footer. ([#2219](https://github.com/matrix-org/matrix-spec/issues/2219))
+- Inline Olm & Megolm specifications. ([#2226](https://github.com/matrix-org/matrix-spec/issues/2226), [#2241](https://github.com/matrix-org/matrix-spec/issues/2241), [#2242](https://github.com/matrix-org/matrix-spec/issues/2242))
+- Silence failing redocly-cli rule. ([#2238](https://github.com/matrix-org/matrix-spec/issues/2238))
+- Use NPM Trusted Publishers for publishing `@matrix-org/spec` to npm. ([#2239](https://github.com/matrix-org/matrix-spec/issues/2239))
+- Add version picker in the navbar. ([#2256](https://github.com/matrix-org/matrix-spec/issues/2256), [#2258](https://github.com/matrix-org/matrix-spec/issues/2258), [#2259](https://github.com/matrix-org/matrix-spec/issues/2259), [#2260](https://github.com/matrix-org/matrix-spec/issues/2260), [#2261](https://github.com/matrix-org/matrix-spec/issues/2261), [#2264](https://github.com/matrix-org/matrix-spec/issues/2264), [#2268](https://github.com/matrix-org/matrix-spec/issues/2268))
+- Add a list of endpoints to the top of each spec page. ([#2262](https://github.com/matrix-org/matrix-spec/issues/2262))