Hi, I'm looking to update our mail servers which are now long in the tooth. As part of the upgrade I'd like to move from using courier to dovecot as the overall volume of mail being stored per user is causing courier to grind badly in webmail. Current servers are running ISPconfig 220.127.116.11 My question is how would you do the change on live servers? 1) Create new Debian Wheezy server with Dovecot running on it and import the mail somehow. How would you keep user account details, mail UID etc, some of the users have very slow connections and large mailboxes so I can't have them redownload the mail again. 2) Create a new Debian Wheezy server with Courier and simply copy the var/vmail folders and ISPconfig database to the new server, then migrate the new server from Courier to Dovecot. Has anyone got a decent description of how to migrate from courier to dovecot with ISPconfig. 3) Any other thoughts I have tried working through option 2 but have had issues with the dovecot migration where I'm getting stuck having updated the folders using courier-dovecot-migrate.pl and then installing dovecot (apt-get install dovecot-imapd dovecot-pop3d). I think the issue is simply in ISPconfig where I tell it to use Dovecot but am then a little confused as to what to set for mail filter syntax and how to get that working if it needs to be sieve. Anyway my misconfiguration results in an authentication error when trying to login using roundcube. Any help or advice is greatly appreciated.