Update app.py

app.py

@@ -1,8 +1,9 @@
-# 4/29/2024
+# 5/1/2024
 
 # This version added saving chat history to a log file (need persist data from a space to a dataset)
 # Updated the GPT model to gpt-4
 # Add timestamp and ip address
+# upgrade llama-index to version 0.10: migrate from ServiceContext to Settings
 
 # 2/23/2024
 # This version uses different method in llama index to define llm model
@@ -41,7 +42,7 @@ session_id = uuid4()
 # deprecated
 storage_context = StorageContext.from_defaults(persist_dir='./')
 # gpt-3.5_turbo is the current default model
-Settings.llm = OpenAI(temperature=0.5, model="gpt-4")
+Settings.llm = OpenAI(temperature=0.5, model="gpt-3.5_turbo")
 #service_context = ServiceContext.from_defaults(llm=llm_predictor)
 #index = load_index_from_storage(storage_context, service_context=service_context)
 index = load_index_from_storage(storage_context)