On Wed, 2010-06-16 at 14:49 +0100, Gavin Lawrie wrote:
I had a look on the Dovecot Wiki and under migration are discussions about various other mail systems, but I don't know enough about these to tell if they would also apply to CGP.
I don't know what CGP's mboxes and maildirs look like. If you don't care that your users redownload mails (worse for POP3), the migration should be easy (e.g. imapsync as mentioned). If you do care, there are two possibilities two preserve UIDs:
a) Write some script to migrate CGP mboxes and maildirs to a format that Dovecot understands. You could keep using both mboxes and maildirs, but a single user can't have both.
b) Write IMAP backend to dsync (http://wiki2.dovecot.org/Tools/dsync) or possibly to Dovecot's lib-storage. Then use dsync to migrate users.
Probably it'll be easier to do a), but b) would be a really nice new feature, also for others for migrating from other servers. :)