diff --git a/zerorpc/events.py b/zerorpc/events.py
index f87d0b5..998ef14 100644
--- a/zerorpc/events.py
+++ b/zerorpc/events.py
@@ -210,7 +210,10 @@ def pack(self):
 
     @staticmethod
     def unpack(blob):
-        unpacker = msgpack.Unpacker(raw=False)
+        if sys.version_info < (3, 0):
+            unpacker = msgpack.Unpacker()
+        else:
+            unpacker = msgpack.Unpacker(raw=False)
         unpacker.feed(blob)
         unpacked_msg = unpacker.unpack()