[Dovecot] Disconnect users for a distinct period of time?

[Michael Grimm]

Hi --

Today, I've learned who to disable incoming mail delivery to dovecot (accepted by postfix), temporarily. Now, I would like to know if there is a way to make a "doveadm kick -A" a permanent disconnect until one would allow reconnects, again? This should be done *without* shutting down dovecot or *extensive* re-configuration. A "doveadm block -u <joe> -m 'sorry: running maintenance, please, come back later'" alike tool/funtionality would be ideal. 

Background: I would like to avoid any modification of my user's maildirs by a running dovecot server while modifying maildir formats, mdbox_rotate_size setting, and alike, where I would need doveadm/dsnyc access to userdb. (I know there a ways to achieve this without downtimes, and I have already done so.)

I just want to be sure that I haven't overseen such a tool/functionality in the documentation. Did I or didn't I?

Thanks and regards,
Michael