diff --git a/main.py b/main.py
index 3fd073d..831c175 100644
--- a/main.py
+++ b/main.py
@@ -194,6 +194,10 @@ def onSent(params, files, callback_url):
     print('onSent')
 
 
+def onDelivered(params, files, callback_url):
+    print('onDelivered')
+
+
 def main():
     print('Use Control-C to exit')
     logging.basicConfig(level=logging.DEBUG)
@@ -204,6 +208,7 @@ def main():
     server.register_function(auth_challenge)
     server.register_function(accept)
     server.register_function(onSent)
+    server.register_function(onDelivered)
 
     thread = threading.Thread(target=run_tasks)
     thread.start()