You are welcome!
Automatic updates are only available after version 4.8.2. In this case you will have to update manually. It's basically a re-download and re-installation of the plugin. Please follow this brief guide for that: https://goo.gl/AG4cCM
After the manual update, the new feature will appear, where you will be able to activate your purchase code.Best,
If you like my products, don't forget to rate them on codecanyon :)