Update app.py

app.py

@@ -394,7 +394,7 @@ def chatbot_fn(user_message, history):
     messages = system_messages + history + [{"role": "user", "content": user_message}]
 
     payload = {
-        "model": "chatgpt-4o-latest",
+        "model": "gpt-4.1",
         "messages": messages,
         "temperature": 0.2,
         "top_p": 1,