The new Debian version “Trixie” has been available for upgrading from Debian “Bookworm” for several weeks now – and as a result, some of my readers have decided to update their mail server setup from my “Mail server with Dovecot, Postfix, MySQL, and Rspamd on Debian 10 Buster [v1.0] (German)”. The setup described for Debian Buster works just as well for Debian Bookworm – but Debian Trixie brings a change:

The latest Debian version makes a leap to Dovecot 2.4 with the included Dovecot version. This means that old Dovecot configurations are no longer compatible!

The configuration syntax has changed significantly in some respects, and old configurations from previous Dovecot versions can no longer be read. This article discusses the changes in the new version 2.4 and explains the migration using the example of the mail server instructions mentioned above. All changes take place in the file /etc/dovecot/dovecot.conf. No further changes (e.g., to the database schema or similar) are necessary.

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