All it means is that the host is running an old/newer version than you are. Find another server, or wait for it to be patched.
Happens every time there is a new update. It will take a few hours until all the servers are updated and restarted. Most server admins put something like 'updated' or 'new version' in the titles. Look out for those servers.
ALSO this bug should be fixed starting with the first post-launch update. With every update, older versions will stop displaying in the server list. The beta servers have a bug that prevents us from being able to filter them out.
As far as I can tell, all of the launch day server's ARE being filtered out and only the update 1 servers are showing. As I mentioned there is a small and shrinking group of servers from beta that were bugged and we can't force them to be filtered out. We'll see if there is something we can do to make em vanish with the next update.
Just how big is this number of beta servers? The problem will sort itself out eventually, and if there's a small enough fraction of servers then why bother?