Steps on performing an Owncloud update in version 8.x. This did not work when upgrading from 8.04 to 8.1. See post on upgrading between major versions.
backup data folders
Simply copy your config and data folder (or even your whole ownCloud install and data folder) to a place outside of your ownCloud environment. You could use this command:
rsync -Aaxv -delete /media/media.serv/owncloud/ /media/backup.serv/backup/temp/owncloud-dirbkp_`date +”%Y%m%d”`/
You must undo strong permissions and directory ownership for updates
https://doc.owncloud.org/server/8.0/admin_manual/maintenance/update.html
chown -Rv www-data:www-data /var/www/cc.com/owncloud
Run owncloud updater from administration menu
data backup done by owncloud. Here is your backup: /media/media.serv/owncloud/data/updater_backup/8.0.0.7-3a8eb931
from command line
must be run from owncloud folder
cd /var/www/cc.com/owncloud/
sudo -u www-data php occ upgrade
Reapply strong permissions on directories
reference: https://doc.owncloud.org/server/8.0/admin_manual/maintenance/update.html#setting-strong-permissions
/data, /apps, and /config are www-data:www-data; everything else root:www-data
my script to set permissions
/usr/local/bin/owncloud.set.permissions.sh