We've been in the process of migrating from our old server to our new server for at least a year and a half. This weekend, we flipped the switch, at least in the sense that all users now pull mail off of the new server. I think all of the web traffic goes to the new server as well.
John is now passing around an engineering pad with the files he's just finished editing. In theory, everything works. He's ready to flip the switch.
Considering that I just spent two hours debugging my SMTP configuration, either we've already achieved breakage so things should work now (gambler's fallacy) or things are about to become slightly more interesting.
As long as I can submit the book to production tomorrow, I will be happy. If I disappear for a few days, I'll be napping.