Some time later…
The forum has now been moved from forum.sympl.host to forum.sympl.io, and the wiki and others should follow soon.
Everything else should be unchanged, with the only difference being the ability to log in via GitLab now being removed - it was using a third party plugin for the forum, required full access to a users account at GitLab, so I’ve now disabled that functionality, although it looks like it wasn’t heavily used. If someone was using it, please create a new account either directly or via one of the other methods and let me know, and I’ll link the accounts.