1 files changed, 6 insertions, 4 deletions
diff --git a/synapse/replication/tcp/commands.py b/synapse/replication/tcp/commands.py
index ccc7f1f0d1..f33801f883 100644
--- a/synapse/replication/tcp/commands.py
+++ b/synapse/replication/tcp/commands.py
@@ -293,20 +293,22 @@ class FederationAckCommand(Command):
 
     Format::
 
-        FEDERATION_ACK <token>
+        FEDERATION_ACK <instance_name> <token>
     """
 
     NAME = "FEDERATION_ACK"
 
-    def __init__(self, token):
+    def __init__(self, instance_name, token):
+        self.instance_name = instance_name
         self.token = token
 
     @classmethod
     def from_line(cls, line):
-        return cls(int(line))
+        instance_name, token = line.split(" ")
+        return cls(instance_name, int(token))
 
     def to_line(self):
-        return str(self.token)
+        return "%s %s" % (self.instance_name, self.token)
 
 
 class RemovePusherCommand(Command):