dovecot - Mar 2015 - Problem with replication ("Fatal: -N parameter requires syncing with remote host")

Switching to official dovecot-ee version solved my sync/backup issues, also on
Ubuntu. The 12.04 package works on 14.04. It's free and should update fine.
Backup your config files first (dovecot and postfix if you use that)!

http://shop.dovecot.fi/home/8-dovecot-ee-repository-access.html