Finally I’ve started the official migration of my production server from the Courier programs to Dovecot. I’ve done it several times on a test server but that is nothing compared to doing it or real on a server where there are a lot more emails and users working on.
I already ran into some problems that I haven’t seen one any of my test runs, which shows that it was good to do this upgrade myself for real before posting the full writeup. I’m posting the migration in several independent steps which you can do at your own leisure and speed. After each step you will have a fully functioning mailserver where only a small part of the setup has been changed. In this manner everything should be manageable and hopefully will not pose to many issues.
In the first step we are going to replace the Courier IMAP server with the Dovecot IMAP server. The instructions will work for Leopard and Snow Leopard. The next step will be about replacing Courier Auth with the Dovecot Auth module.
But no time to waste, read the first step in migrating from Courier to Dovecot.