How to deactivate the maintenance mode on NextCloud

Problem:

NextCloud is permanently in maintenance mode after the update

Solution on Debian:

Change the maintenancemode entry to "false"

in the file

/var/www/owncloud/config/config.php

Solution on OpenSuse:

Change the maintenancemode entry to "false"

in the file

/srv/www/htdocs/owncloud/config/config.php