1 files changed, 2 insertions, 1 deletions
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index f801fb5324..92f64619c9 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -31,10 +31,11 @@ class ApplicationService(object):
     # values.
     NS_LIST = [NS_USERS, NS_ALIASES, NS_ROOMS]
 
-    def __init__(self, token, url=None, namespaces=None):
+    def __init__(self, token, url=None, namespaces=None, txn_id=None):
         self.token = token
         self.url = url
         self.namespaces = self._check_namespaces(namespaces)
+        self.txn_id = None
 
     def _check_namespaces(self, namespaces):
         # Sanity check that it is of the form: