Since #1521, the app refuses to connect to servers older than Zulip Server 7. That means we can simplify away all the spots in our codebase where we have logic to accommodate older versions of the Zulip server.

The previous issue #268 was for removing the code for supporting Zulip Server 4, relying on server 5, as marked by comments TODO(server-5). This one is for relying on server 6, as marked by comments TODO(server-6). For details, see #268 and the previous issues linked from there.

References

• Previous round of the same thing: Require Zulip Server 5 #268
• PR that implemented the previous round: Start Requiring Zulip Server 5 #904
• PR that disallowed connecting to older servers (a prerequisite for this issue): api: Like zulip-mobile, don't allow connecting to Zulip Server <7.0 #1521