Require Zulip Server 8 #1839
Description
As discussed in #1521, the Zulip Server versions 7.x are all now outside our 18-month support window. So we can happily drop support for them, bumping our minimum to 8.0.
Then when we do, we can clear out all the TODO(server-8) comments, just like #1838 and previous issues linked from there describe for previous Zulip Server versions.
(Then for the next round: looking at https://blog.zulip.com/tag/release-announcements/, the last 8.x release was 2024-08-01; so we can drop support for 8.x and require 9.0+ any time 18 months after that, meaning 2026-02-01 and later.)
References
- Previous round of bumping the threshold: api: Like zulip-mobile, don't allow connecting to Zulip Server <7.0 #1521
- Previous round of clearing out old compatibility code: Rely on Zulip Server 7 APIs #1838
- Policy on timeline for Zulip clients to support old server versions: https://zulip.readthedocs.io/en/latest/overview/release-lifecycle.html#client-apps
- History of Zulip Server releases: https://blog.zulip.com/tag/release-announcements/