Once that was out of the way, the only other hurdle was that the new server software requires SMTP authentication, which the old one didn't, so I had to run around checking off the little box in everyone's Outlook settings to do just that, and then figuring out how to do the same with our fax machines and other odd SMTP sources.
Still seeing some odd behaviors here and there (the fabled "No transport provider" error has been popping up a lot), but other than that things seem to be working.
