diff --git a/src/applications/differential/herald/HeraldDifferentialDiffAdapter.php b/src/applications/differential/herald/HeraldDifferentialDiffAdapter.php
--- a/src/applications/differential/herald/HeraldDifferentialDiffAdapter.php
+++ b/src/applications/differential/herald/HeraldDifferentialDiffAdapter.php
@@ -57,4 +57,8 @@
     return pht('New Diff');
   }
 
+  public function supportsWebhooks() {
+    return false;
+  }
+
 }