If you are using a key on an old version (that is not beta), Badspot revokes your key, I believe.
No, you just can't connect to the master server.
This is what I was wondering, so that means no one could host a V-21 server.
Well, I think they could still connect through IP.
V8 will always be my favorite though.
What if Badspot reads this and tells the master server not to accept anything under v21? Also, that idea plain sucks... Noone will be online because everyone plays a different version...