diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 097456be4f..3c6f2fe989 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -924,9 +924,7 @@ class SyncHandler(object):
                     tags=pagination_config.tags,
                 )
 
-                to_sync_map = {
-                    key: value for key, value in cutoff_list
-                }
+                to_sync_map = {key: value for key, value in cutoff_list}
             else:
                 to_sync_map = {}
 
diff --git a/synapse/types.py b/synapse/types.py
index f0ad527bc0..cfd3e7328b 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -18,7 +18,7 @@ from synapse.api.errors import SynapseError
 from collections import namedtuple
 
 from unpaddedbase64 import encode_base64, decode_base64
-import msgpack
+import ujson as msgpack
 
 
 Requester = namedtuple("Requester", ["user", "access_token_id", "is_guest"])