version: Update version and changelog following 8.4 release.

docs/overview/changelog.md

@@ -25,6 +25,47 @@ log][commit-log] for an up-to-date list of all changes.
 
 ## Zulip Server 8.x series
 
+### Zulip Server 8.4
+
+_Released 2024-05-09_
+
+- Notably improved the performance of several common API endpoints.
+- Fixed a regression in 8.3 which caused server errors when trying to view
+  message edit history, for messages that had been moved after having previously
+  edited or moved.
+- Fixed a memory leak in the missed-message email worker.
+- Improved documentation and support for [running the PostgreSQL service on a
+  separate server](../production/postgresql.md#separate-postgresql-database).
+- Added support for PostgreSQL streaming replication without wal-g or S3
+  backups.
+- Added support for including [warm-standby remote PostgreSQL
+  servers](../production/postgresql.md#postgresql-warm-standby) in the
+  PostgreSQL server list.
+- Started always installing the version of `postgresql-client` which matches the
+  PostgreSQL server’s version.
+- Increased the visual prominence of reactions you have added/upvoted.
+- The ‘default' topic visibility icon is no longer displayed in the inbox view,
+  for a cleaner look.
+- Fixed confusing wording in the [Alertmanager
+  integration](https://zulip.com/integrations/doc/alertmanager).
+- Started allowing DMs to bots and to oneself, regardless if [DMs are in general
+  restricted](https://zulip.com/help/restrict-direct-messages).
+- Notices indicating that “push notifications are not working” are now
+  considerably more robust to temporary networking failures reaching the mobile
+  push notifications service.
+- Improved startup time of Zulip services by only performing configuration
+  checks once, rather than in every service at startup.
+- Improved how timeouts function in potentially long-running requests.
+- Added checks that `./manage.py register_server --rotate-key` can edit the
+  secrets file before rotating the secret.
+- Fixed sorting of “invited by” column in the invitations settings panel.
+- Fixed several non-exploitable HTML injection bugs.
+- Fixed a bug when “Direct messages” are collapsed in the left sidebar, which
+  could cause a DM conversation to be incorrectly highlighted after navigating
+  to a different conversation.
+- Upgraded Python dependencies.
+- Updated translations.
+
 ### Zulip Server 8.3
 
 _Released 2024-03-19_

version.py

@@ -14,7 +14,7 @@ ZULIP_VERSION = lines.pop(0).strip()
 ZULIP_MERGE_BASE = lines.pop(0).strip()
 
 LATEST_MAJOR_VERSION = "8.0"
-LATEST_RELEASE_VERSION = "8.3"
+LATEST_RELEASE_VERSION = "8.4"
 LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.com/2023/12/15/zulip-8-0-released/"
 
 # Versions of the desktop app below DESKTOP_MINIMUM_VERSION will be