I have an iRedMail server running (postfix + dovecot as an IMAP server) on a Debian Xen guest machine. By a mistake the iscsi disk, where users emails are stored, was deleted. There is another copy of this disk from December 30th 2014. There is a full backup of users email from January 16th 2015. So all user emails from the beginning to January 16th were restored.
The problem is when users open their email clients and the synchronization process with IMAP server begins all downloaded emails from January 16th till today (January 31th) will be deleted from their machines. How should I configure dovecot IMAP server so that these emails will be synchronized back to the IMAP server?