Our new IMAP servers were successfully deployed today after upgrading the new ZFS based storage, which resolved an error that had previously caused problems. The technical details of this error can be found in the official bug report from the operating system distributor.
The combination of new, powerful IMAP servers and a modern, ZFS based SAN (Storage Area Network) should significantly improve IMAP performance in the coming days and weeks as we move email accounts to the new storage unit.
Additionally, the new IMAP servers support Perfect Forward Secrecy on SSL (encrypted) connections, which prevents an unlikely eavesdropper to decrypt the communication between client and server.
You do not have to change anything in your email client to enjoy these new technologies, but do let us know if you experience any problems.