I have just upgraded Debian Squeeze > Wheezy. Dovecot is now version 2.1.7.
When starting Dovecot you will get warning about the syntax of the dovecot.conf file. With a version of the file automatically updated by Dovecot I get a Perl exception in Usermin. With a manually config'd file I could not get auth working, connection was always refused. With the default conf file supplied I could not get correct maildirs working. Studying the documentation did not enable me to sort it out because I was could not find documentation on the auth setup which works with Virtualmin.
If anyone can offer advice about how to the mod the dovecot.conf file to get rid of the syntax warnings, that would be welcome. However, the old version of the file is working. My advice to others contemplating this upgrade is to ignore the syntax warnings when starting Dovecot, and don"t mess with the file, or at least be sure to take a backup copy before changing it. I did have to uncomment the lines pointing to ssl certificates to get Dovecot to start, but beyond that an untouched file kept from the pre-upgrade version was the only way I could get Dovecot working.
[EDIT] For others having problems, the doveconf script which autogenerates a conf file compatible with the new version does work. It was a long night.... don"t manually edit the conf file if you are tired...j
Maybe this will change when Virtualmin package is released for Wheezy, but for now Just run the script which generates and updated conf file:
doveconf > dovecot.conf-new
mv dovecot.conf dovecot.conf-backup
mv dovecot.conf-new dovecot.conf
service dovecot restart (or /etc/init.d/dovecot restart should do it: if not just put back your backed up file and ignore the warnings, it still worked but only with the paths to SSL files uncommented)