diff --git a/webtools/bugzilla/Bugzilla/Mailer.pm b/webtools/bugzilla/Bugzilla/Mailer.pm
index 15df6bddd40d..2105d38ae53d 100644
--- a/webtools/bugzilla/Bugzilla/Mailer.pm
+++ b/webtools/bugzilla/Bugzilla/Mailer.pm
@@ -196,6 +196,7 @@ sub encode_message_entity {
         $head->mime_attr('Content-Type.charset' => 'UTF-8');
     }
 
+    $head->mime_attr('MIME-Version' => '1.0');
     $head->fold(75);
     return $entity;
 }