diff --git a/lib/py/src/TMultiplexedProcessor.py b/lib/py/src/TMultiplexedProcessor.py
index 8d929ac..bd10d9b 100644
--- a/lib/py/src/TMultiplexedProcessor.py
+++ b/lib/py/src/TMultiplexedProcessor.py
@@ -24,8 +24,18 @@
 
 class TMultiplexedProcessor(TProcessor):
     def __init__(self):
+        self.defaultProcessor = None
         self.services = {}
 
+    def registerDefault(self, processor):
+        """
+        If a non-multiplexed processor connects to the server and wants to
+        communicate, use the given processor to handle it.  This mechanism
+        allows servers to upgrade from non-multiplexed to multiplexed in a
+        backwards-compatible way and still handle old clients.
+        """
+        self.defaultProcessor = processor
+
     def registerProcessor(self, serviceName, processor):
         self.services[serviceName] = processor
 
@@ -38,10 +48,14 @@
 
         index = name.find(TMultiplexedProtocol.SEPARATOR)
         if index < 0:
-            raise TProtocolException(
-                TProtocolException.NOT_IMPLEMENTED,
-                "Service name not found in message name: " + name + ".  " +
-                "Did you forget to use TMultiplexedProtocol in your client?")
+            if self.defaultProcessor:
+                return self.defaultProcessor.process(
+                    StoredMessageProtocol(iprot, (name, type, seqid)), oprot)
+            else:
+                raise TProtocolException(
+                    TProtocolException.NOT_IMPLEMENTED,
+                    "Service name not found in message name: " + name + ".  " +
+                    "Did you forget to use TMultiplexedProtocol in your client?")
 
         serviceName = name[0:index]
         call = name[index + len(TMultiplexedProtocol.SEPARATOR):]
diff --git a/lib/py/src/protocol/__init__.py b/lib/py/src/protocol/__init__.py
index 7148f66..06647a2 100644
--- a/lib/py/src/protocol/__init__.py
+++ b/lib/py/src/protocol/__init__.py
@@ -18,4 +18,4 @@
 #
 
 __all__ = ['fastbinary', 'TBase', 'TBinaryProtocol', 'TCompactProtocol',
-           'TJSONProtocol', 'TProtocol']
+           'TJSONProtocol', 'TProtocol', 'TProtocolDecorator']