diff --git a/src/applications/differential/replyhandler/DifferentialReplyHandler.php b/src/applications/differential/replyhandler/DifferentialReplyHandler.php
index 9c2441c89b..b16dbde854 100644
--- a/src/applications/differential/replyhandler/DifferentialReplyHandler.php
+++ b/src/applications/differential/replyhandler/DifferentialReplyHandler.php
@@ -16,7 +16,7 @@
  * limitations under the License.
  */
 
-final class DifferentialReplyHandler extends PhabricatorMailReplyHandler {
+class DifferentialReplyHandler extends PhabricatorMailReplyHandler {
 
   private $receivedMail;