LicenseBox is a full-fledged license and updates manager for PHP applications, plugins/themes etc. LicenseBox is made up of two parts, the first part is the main script itself this will be installed/hosted on your own server and the second part is a single .php script this will be included in your PHP application on which you wish to use LicenseBox.
Demo: https://codecanyon.net/item/licensebox-php-license-and-updates-manager/22351237