I adopted the below methods from upgrading Wordpress manually and tweak the process for manually upgrading OwnCloud:
Backup
Navigate to your OwnCloud location and run the following to backup your OwnCloud.
rsync -a owncloud/ owncloud.backup/
Download Latest OwnCloud
wget https://download.owncloud.org/community/owncloud-9.1.1.tar.bz2
replace the link with the latest bz2 file.
Extract the Package
bzip2 -d owncloud-9.1.1.tar.bz2
tar xvf owncloud-9.1.1.tar
this creates "owncloud" directory
Copy the Updated Files
rsync -rtv new_path_version/owncloud/ old_path_version/owncloud/
this syncs any file that has been changed from the new location/version to the old location
Navigate to The Site
Load the site and it will ask you to upgrade the database. Don't do it over the UI, do it manually
Database Upgrade Manually
run the following command from the "owncloud" directory
To test the database upgrade:
sudo -u www-data php occ upgrade --dry-run -v
To execute the database upgrade:
sudo -u www-data php occ upgrade -v
