1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/rest/client/keys.py b/synapse/rest/client/keys.py
index eb1b85721f..e3f454896a 100644
--- a/synapse/rest/client/keys.py
+++ b/synapse/rest/client/keys.py
@@ -208,7 +208,9 @@ class KeyChangesServlet(RestServlet):
 
         # We want to enforce they do pass us one, but we ignore it and return
         # changes after the "to" as well as before.
-        set_tag("to", parse_string(request, "to"))
+        #
+        # XXX This does not enforce that "to" is passed.
+        set_tag("to", str(parse_string(request, "to")))
 
         from_token = await StreamToken.from_string(self.store, from_token_string)