diff --git a/IPython/frontend/html/notebook/routers.py b/IPython/frontend/html/notebook/routers.py
index 1321848..6cf5dc3 100644
--- a/IPython/frontend/html/notebook/routers.py
+++ b/IPython/frontend/html/notebook/routers.py
@@ -84,7 +84,7 @@ class ZMQStreamRouter(Configurable):
be sent back to the browser.
"""
idents, msg_list = self.session.feed_identities(msg_list)
- msg = self.session.unpack_message(msg_list)
+ msg = self.session.unserialize(msg_list)
msg['header'].pop('date')
return json.dumps(msg)