diff --git a/changelog.d/11460.misc b/changelog.d/11460.misc
new file mode 100644
index 000000000000..fc6bc82b364a
--- /dev/null
+++ b/changelog.d/11460.misc
@@ -0,0 +1 @@
+Fix a bug introduced in 1.47.0 where `send_join` could fail due to an outdated `ijson` version.
diff --git a/tests/federation/transport/test_client.py b/tests/federation/transport/test_client.py
index 0b191599618a..a7031a55f28c 100644
--- a/tests/federation/transport/test_client.py
+++ b/tests/federation/transport/test_client.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 import json
 
 from synapse.api.room_versions import RoomVersions