To upgrade Nextcloud is actually pretty simple. The instructions are very similar to my post on Migrate from ownCloud 9.1.1 to Nextcloud 10.0.2.
Please note that I have created a directory “/opt/owncloud-install/” which I use to backup files to when performing an upgrade. You can have a directory named something else, the name isn’t important. Also my Nextcloud installation is in a directory named “/var/www/owncloud”, I found it easier to leave the directory name exactly the same when I migrated from ownCloud to Nextcloud.
1. Download Nextcloud server version 11.0.0
2. Stop your webserver
3. Backup (move) your config.php file and your data folder
4. Delete your ownCloud folder
5. Extract Nextcloud 11.0.0 (please note that the tar ball doesn’t include a data folder or a config.php file)
6. You now have a folder named nextcloud, I’m going to rename this folder to owncloud
7. Move the config.php file and your data folder which you backed up in Step 3
8. Set the correct ownership for your Nextcloud instance (the files in the tar ball are owned by nobody)
9. Start your webserver
10. Complete the upgrade to Nextcloud 11.0.0