Problem
Nextcloud in maintenance mode after update.
Solution
Use the following commands to verify and stop maintenance mode on UCS server with nextcloud installation.
Verify:
root@ucs:~# univention-app shell nextcloud sudo -u www-data php /var/www/html/occ maintenance:mode
End maintenance mode:
root@ucs:~# univention-app shell nextcloud sudo -u www-data php /var/www/html/occ maintenance:mode --off