* Remove unstable support for `m.room_key.withheld` ([\#2512](https://github.com/matrix-org/matrix-js-sdk/pull/2512)). Fixes #2233. * 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)). * 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.