Open X-Change making a *universally breaking* change in config format & removing features from #Dovecot in the 2.3->2.4 upgrade is telling. That they removed some core features (e.g. unix login auth) inks in the drawing. They are tired of having the world's de facto default open source mailstore server, they want the world's most lucrative mailstore server.

And the page explaining the changes at https://doc.dovecot.org/2.4.0/installation/upgrade/2.3-to-2.4.html is basically a big fat FUCK YOU to the Dovecot Community.
#Sysadminnery