Only 2.3.x.x version osCommerce Some addons use a hook system, use for compatibility. This is commit @haraldpdl Hooks #254 https://github.com/osCommerce/oscommerce2/pull/254/files Install ------- Unzip the archive and upload the file on server. In /includes/application_top.php Add code to the bottom of the file, before the last closing ?> require(DIR_FS_CATALOG . 'includes/classes/hooks.php'); $OSCOM_Hooks = new hooks('shop'); $OSCOM_Hooks->register(basename($PHP_SELF, '.php')); In /admin/includes/application_top.php Add code to the bottom of the file, before the last closing ?> require(DIR_FS_CATALOG . 'includes/classes/hooks.php'); $OSCOM_Hooks = new hooks('admin'); $OSCOM_Hooks->register(basename($PHP_SELF, '.php'));