Command line update on CentOS7 just worked....
From the nextcloud root directorysudo -u apache php ./updater/updater.phar sudo -u apache php ./occ upgrade
Maybe 2 minutes total.
Worked here to. Going from 12-beta2 to 12-beta4
Won't work for me because I have the improved directory security. You have to chown things back around for the updater to work.