[Emera]

If you want to force it just for your server then do a client version check when they log in and boot them off if their version isn't high enough. Either that, or script some anti-hack checks. You can find some decent ones by searching these forums I think, and if there's anything you need that isn't on the forums, I've got backups of some I've made before on my DropBox so just send me a forum PM and I might be able to help you out.