Nextcloud released update 11.0.2.(February 27 2017) and if you are using package from "Jurisic repository". I will demonstrate how to upgrade from 11.0.1 to 11.0.2. in this short guide.
Check changelog before upgrade on link https://nextcloud.com/changelog/
As you can see i got message and notification on my server (Update to Nextcloud 11.0.2 is available) which tells me that now is time for upgrade.
First we need to update with apt-get:
apt-get -y update apt-get upgrade
Choose "Y" to start the installation, wait fo finish the download and package will set Nextcloud server in Maintenance mode.
Now start upgrade Nextcloud server with OCC tools:
sudo -u www-data /var/www/nextcloud/occ upgrade
After upgrade turn off Maintenance mode and enable apps:
sudo -u www-data /var/www/nextcloud/occ maintenance:mode --off
Check which app is disabled after upgrade and enable (in my case only contacts):
sudo -u www-data /var/www/nextcloud/occ app:enable contacts
Nextcloud server is ready for use. Enjoy !