diff --git a/booking.module b/booking.module
index b9287ec..86322fd 100644
--- a/booking.module
+++ b/booking.module
@@ -876,8 +876,8 @@ function booking_mail($key, &$message, $params) {
  * Implements hook_mail_alter()
  */
 function booking_mail_alter(&$message) {
-	// $message['id'] comes from {module_name}_{email_key}
-	$implemented_message_ids = array('booking_registration_mail', 'booking_email_custom', 'registration_mail_bal_outstanding');
+	//message id used here comes from {module_name}_{email_key}
+	$implemented_message_ids = array('booking_registration_mail', 'booking_booking_email_custom', 'booking_registration_mail_bal_outstanding');
 
 	if (in_array($message['id'], $implemented_message_ids)) {
   //if($message['id'] == 'booking_registration_mail') {