I had to re-install Dovecot over the weekend because something went wrong internally that I was unable to identify.

     I installed with mostly default settings, changing on a few things I knew were necessary for our installation.

     This morning it reached some of the internal limits set.  I’ve addressed those issues today.  Things like the total number of clients that can be active at once.  I would have thought 1000, which is the default sufficient, but many people have half a dozen devices polling so it was not.  I bumped that to 5000.  Also fixed some configuration issues with locking, indexes, added some client bug workarounds to work around bugs in Thunderbird and Outlook, Outlook chokes and NULLS, and Thunderbird adds an extra ‘/’ to mail paths.  A few other minor tweaks but seems to be working okay now.