How to update my gmod server to the new version?

[Zipline100]

Ok so here's whats happening -
Ever since gmod updated yesterday nobody can connect to my server (running off a virtual server) it gives them the message "server uses incorrect class files" and kicks them out. Ive tried restarting it multiple times but still nothing. What do I need to do to update it?

[soja]

Run steamcmd and update the server files. The same procedure as when you first installed the server.

[Zipline100]

But how do I do it without deleting my server files? Installing it again will delete them

[soja]

No it wont