Hi Bennet,
First off all, you need to register a Download ID through this link:https://www.joomdonation.com/download-ids.html
Then, please enter Download ID into OS Property Configuration page > Tab: Download ID.
You also need to make sure the installer plugin: OS Property - Update package is published
After that, you can try to upgrade OS Property extension from Back-end of your Joomla site.
Good luck
Dam
