I wonder if this should be done via ftp and re-uploading the codes or there is a panel based setting.
There is an option in
/settings/info in the right side bar, but the updater is hardcoded to the stable branch. If you use the next branch, this update would be a downgrade.
If you have access via SSH, the fastest way to update is
git clone (install) and
git pull (update).
yes you can update your cockpit installation by just uploading the files of a new version via FTP - just make sure to keep your storage dir! IF you remove your storage dir all data will be lost - all other dirs are not relevant to data you put into cockpit
Don’t forget the config folder if you don’t want to lose changes in config.yaml, modifications in your custom bootstrap.php or your translation files…