For those faced with this, give yourself PLENTY of time to work
though the dovecot docs before making the change. The changes are
extensive and other than having the benefit of running dovecot for
almost 20 years, getting dovecot reconfigured and up and running took
the same dive into the docs learning dovecot for the first time did.
(…)
Extending on that advice.
If your old configuration is based on editing the example
configuration shipped with Dovecot 2.3, and your idea is to download the
2.4 example, merge old stuff onto the 2.4 example: don’t. You’re
probably just wasting your time. It seems this approach fails even for
simple configs.
Dovecot devs’ choice to design setting name lookup so configs can
retain the legacy structure, is of great help. This keeps your old
knowledge still mostly correct, even if the underlying model has
changed. But the differences are deep enough that simply renaming a few
things is not working.
Run a diff tool to identify the changes from the defaults. Use the
guide and examples to locate 2.4 versions of the settings. And than
rewrite it from scratch, for 2.4. From what I get this is the only way.
Simple merging or naïve mapping made Dovecot bark at me.
While you’re producing the new configs, dovecot23 provides some
cushion for the time being.
