Update: This is complete.
Update: This is now scheduled for 11pm PST 6/4.
Update: This has been postponed.
Tonight at 11:59pm we are upgrading our IMAP/POP3 proxy servers to a newer version. This upgrade will include several bug/security fixes, as well as allow us to update some of our SSL security settings to more modern standards. The upgrade itself will require all currently connected clients to reconnect, which most clients will do seamlessly. If there are any problems connecting to the IMAP/POP3 service after the update, please contact support.
-SOC