In addition to including the validateaactivatewp.php file to your plugin files, add this code snippet to your main plugin file:
//add licensing support
include_once(WP_PLUGIN_DIR.’/YOUR_PLUGIN_FOLDER_NAME/validateaactivatewp.php’);
if (!function_exists(‘validate_actwp_b44c8b9b7aec232de31fc20dacecf83e’))
die();
validate_actwp_();
NOTE: Make sure you change YOUR_PLUGIN_FOLDER_NAME to the actual folder name of your plugin.