Hi Dams
Indeed, backup_core_only
isn’t used anymore as an app setting.
Now, this option is replaced by a environment variable, more volatile and so, less subject to side effects.
So, now, to create a backup without the data, precede your backup command by BACKUP_CORE_ONLY=1
to set the option.
sudo BACKUP_CORE_ONLY=1 yunohost backup create [...]