ClickBank's Instant Notification Service is a webhook that lets you get transaction notifications in real time. For example, you can use them to inform your membership software when members join/pay/cancel. ClickBank provides the following sample code for PHP: The problem is that the mcrypt libraries - required to decrypt the notification - were abandoned back in 2007, and because of this, use of the library has been deprecated in PHP 7.1 and removed from PHP 7.2 entirely. In … [Read more...] about ClickBank IPN with PHP 7.2 and above