- Return a proper error code when the rooms of an invalid group are requested. ([\#8129](https://github.com/matrix-org/synapse/issues/8129))
- Return a proper error code when the rooms of an invalid group are requested. ([\#8129](https://github.com/matrix-org/synapse/issues/8129))
- Fix a bug which could cause a leaked postgres connection if synapse was set to daemonize. ([\#8131](https://github.com/matrix-org/synapse/issues/8131))
- Fix a bug which could cause a leaked postgres connection if synapse was set to daemonize. ([\#8131](https://github.com/matrix-org/synapse/issues/8131))
- Clarify the error code if a user tries to register with a numeric ID. This bug was introduced in v1.15.0. ([\#8135](https://github.com/matrix-org/synapse/issues/8135))
- Clarify the error code if a user tries to register with a numeric ID. This bug was introduced in v1.15.0. ([\#8135](https://github.com/matrix-org/synapse/issues/8135))
- Fixes a bug where appservices with ratelimiting disabled would still be ratelimited when joining rooms. This bug was introduced in v1.19.0. ([\#8139](https://github.com/matrix-org/synapse/issues/8139))
- Fix a bug where appservices with ratelimiting disabled would still be ratelimited when joining rooms. This bug was introduced in v1.19.0. ([\#8139](https://github.com/matrix-org/synapse/issues/8139))
- Fix logging in via OpenID Connect with a provider that uses integer user IDs. ([\#8190](https://github.com/matrix-org/synapse/issues/8190))
- Fix logging in via OpenID Connect with a provider that uses integer user IDs. ([\#8190](https://github.com/matrix-org/synapse/issues/8190))
- Fixes a longstanding bug where user directory updates could break when unexpected profile data was included in events. ([\#8223](https://github.com/matrix-org/synapse/issues/8223))
- Fix a longstanding bug where user directory updates could break when unexpected profile data was included in events. ([\#8223](https://github.com/matrix-org/synapse/issues/8223))
- Fix a longstanding bug where stats updates could break when unexpected profile data was included in events. ([\#8226](https://github.com/matrix-org/synapse/issues/8226))
- Fix a longstanding bug where stats updates could break when unexpected profile data was included in events. ([\#8226](https://github.com/matrix-org/synapse/issues/8226))
- Fix slow start times for large servers by removing a table scan of the `users` table from startup code. ([\#8271](https://github.com/matrix-org/synapse/issues/8271))
- Fix slow start times for large servers by removing a table scan of the `users` table from startup code. ([\#8271](https://github.com/matrix-org/synapse/issues/8271))
