diff --git a/booking.module b/booking.module
index 2aaa34f..3be6d49 100644
--- a/booking.module
+++ b/booking.module
@@ -882,7 +882,7 @@ function booking_mail_alter(&$message) {
       'MIME-Version' => '1.0',
       'Content-Type' => 'text/html; charset=UTF-8; format=flowed',
       'Content-Transfer-Encoding' => '8bit',
-      'X-Mailer' => 'Drupal',
+      'X-Mailer' => 'Drupal1',
     );
   }else{
     $headers = array(