[qualiteam]

It depends on your hosting provider and the server configuration.

For a better security you should consult with your server administrator on what file permissions should be set to allow PHP scripts overwrite files of X-Cart 5 files during the upgrade routine, but prevent other users on the same shared server from viewing or changing these files.

Some servers use your user account - on these 755 for directories and 644 for files should work. Others run PHP scripts as an "apache" users - on these you may need to set the permissions to 775/664 or 777/666.