I'm really itching to switch from Courier to Dovecot for IMAP access. While I'm at it, I'm planning to phase out POP3.
Instead of MySQL, I want to use LDAP - its lighter and simpler and just as easy to replicate.
I'll continue to use Postfix; and that way I can migrate from CDB to LDAP too.
My plan to switch to Dovecot will likely go like this:
I've done this before so it shouldn't be too bad.
UPDATE: I've done it! Most of my notes are over at the Docunext Wiki, so check 'em out: