We encourage our customers to use IMAP but we still have POP users. The problem to ask people to change from POP to IMAP is that as they probably did not enabled "leave messages on the server".
Depending on their mail client that would probably means switching to IMAP means losing all their mails and that would be a support nightmare.
As for the POP issue on the beta, we don't use it in production environnement yet, so we have not enough POP real daily usage testing on the beta with POP...
Kind regards
EDIT: Also there are usage case where POP is required. For example we use SmarterTrack that pull support tickets with... POP (no IMAP option as far as I know).
If it starts missing tickets when we update SmarterMail, that will be a problem.
Sébastien Riccio
System & Network Admin
https://swisscenter.com