Update app.py

app.py

@@ -258,7 +258,7 @@ def respond(message: str, history: List[Dict[str, str]], system_message: str = "
 
     try:
         response = client.chat.completions.create(
-            model="gpt-4-0125-preview",
+            model="gpt-4o-mini",
             messages=messages,
             max_tokens=max_tokens,
             temperature=temperature,