I haven’t tried anything myself. There seems to be a problem with the migration tool, if you perform a manual migration, this can work (I think someone answered in a different topic that it worked for him). It actually works like a manual upgrade:
- make a full backup (all files from data, the database, config/config.php)
- delete all code files (only keep
data/andconfig/-folder) - Download and extract code from https://nextcloud.com/changelog/#latest12
- Fix permissions that webserver user can access files (Debian/Ubuntu:
chown -R www-data:www-data /var/www/nextcloud) - Run upgrade from command line (Debian/Ubuntu:
sudo -u www-data php /var/www/nextcloud/occ upgrade) - In some cases you need to turn off maintenance mode:
sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --off
On other systems, the webserver user is different and not www-data (you can check who is the owner of the data and config folder, this is very likely the right user).