Update app.py

app.py

@@ -65,7 +65,7 @@ QA_PROMPT = PromptTemplate(template=template, input_variables=["question", "cont
 
 def get_chain(vectorstore):
     llm = OpenAIChat(streaming=True, callback_manager=CallbackManager([StreamingStdOutCallbackHandler()]), verbose=True, temperature=0,\
-                    prefix_messages=prefix_messages)
+                    prefix_messages=prefix_messages,model_name='gpt-4-0613')
     qa_chain = ChatVectorDBChain.from_llm(
         llm,
         vectorstore,