- Fix a case where logging contexts would go missing when federation requests time out. ([\#10810](https://github.com/matrix-org/synapse/issues/10810))
- Fix error in deprecated `/initialSync` endpoint when using the undocumented `from` and `to` parameters. ([\#10827](https://github.com/matrix-org/synapse/issues/10827))
- Fix a bug causing the `remove_stale_pushers` background job to repeatedly fail and log errors. This bug affected Synapse servers that had been upgraded from version 1.28 or older and are using SQLite. ([\#10843](https://github.com/matrix-org/synapse/issues/10843))
- Fix a bug in Unicode support of the room search admin API. It is now possible to search for rooms with non-ASCII characters. ([\#10859](https://github.com/matrix-org/synapse/issues/10859))
- Fix a bug introduced in Synapse 1.37.0 which caused `knock` events which we sent to remote servers to be incorrectly stored in the local database. ([\#10873](https://github.com/matrix-org/synapse/issues/10873))
- Fix a bug in Unicode support of the room search admin API breaking search for rooms with non-ASCII characters. ([\#10859](https://github.com/matrix-org/synapse/issues/10859))
- Fix a bug introduced in Synapse 1.37.0 which caused `knock` membership events which we sent to remote servers to be incorrectly stored in the local database. ([\#10873](https://github.com/matrix-org/synapse/issues/10873))
- Fix invalidating one-time key count cache after claiming keys. Contributed by Tulir at Beeper. ([\#10875](https://github.com/matrix-org/synapse/issues/10875))
- Fix application service users being subject to MAU blocking if MAU had been reached, even if configured not to be blocked. ([\#10881](https://github.com/matrix-org/synapse/issues/10881))
- Allow the `.` and `~` characters when creating registration tokens as per the change to [MSC3231](https://github.com/matrix-org/matrix-doc/pull/3231). ([\#10887](https://github.com/matrix-org/synapse/issues/10887))
