Clienet and Server products dont match

[The Spie]

Everytime i join a server it says Client and Server products don't match. Any help?
Im not VAC banned

[Mazakrov]

They haven't updated their servers yet.

[suttles]

They haven't updated.

It is also why my friend's server went from having 10 people at max to having 32.

Hell yes, I love valve.