I’ve been using miab for a few months now, migrated from a roll your own postfix / dovecot / z-push / nextcloud that I’ve been using for years.
I only really use the files function in nextcloud with group folders for our family, but it’s really useful.
I’ve just unlocked the nextcloud that’s embedded in miab and it’s working perfectly for me. I followed the instructions at RainLoop in Nextcloud (MIAB v0.26+ ONLY).