Over on the server mailing lists, it's being reported that the servers aren't being limited to 6 players like they're supposed to and are crashing left and right.

This is on top of the ridiculously large (and thus long) download which our server hasn't finished applying nearly two hours after its release.

Edit: Hopefully we'll see a bugfix release today. On my server (tf2.rbemrose.com, password is hidden based on professorpan's request), it's set to only show 6 visible players. This is a nasty hack, as the bots are showing in player slots despite the fact that they shouldn't. It also means that all but one person could drop during a wave, but no one can join until the wave ends.