A new update to Gmod came out and now i can't join the server.
Are you planning to update it?
No clearly we are just going to let the server stay on the old update forever so that nobody is ever able to join again, thanks for asking.
(Yes, the developers are aware of the update and the server should be up to date soon :>)
It's being worked on now, update just dropped 5 minutes ago
When a Garry's Mod update comes out, they will normally update asap so.
Give them time.