diff --git a/spinel/codec.py b/spinel/codec.py
index 41f2736..68e1f61 100644
--- a/spinel/codec.py
+++ b/spinel/codec.py
@@ -604,7 +604,7 @@ def __init__(self):
         self.wpan_api = None
         self.__queue_prefix = queue.Queue()
         self.prefix_thread = threading.Thread(target=self.__run_prefix_handler)
-        self.prefix_thread.setDaemon(True)
+        self.prefix_thread.daemon = True
         self.prefix_thread.start()
 
     def handle_prefix_change(self, payload):