diff --git a/src/pubsub/pubsub/pubsub_library_v3.py b/src/pubsub/pubsub/pubsub_library_v3.py
index 7cf1193..4160a0b 100644
--- a/src/pubsub/pubsub/pubsub_library_v3.py
+++ b/src/pubsub/pubsub/pubsub_library_v3.py
@@ -166,7 +166,9 @@ class MinimalServiceProvider(Node):
 
     # Insert your callback code here
     def user_defined(self, request, response):
-        """ Write your user defined code here which will be run at every service call
+        """ OLD! Use function parameter srv_callback_fct instead!
+        
+        Write your user defined code here which will be run at every service call
 
         Input:
         * request: srv request class