diff --git a/changelog.d/8262.bugfix b/changelog.d/8262.bugfix
new file mode 100644
index 000000000..2b84927de
--- /dev/null
+++ b/changelog.d/8262.bugfix
@@ -0,0 +1 @@
+Upgrade canonicaljson to version 1.4.0 to fix an unicode encoding issue.
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 2d995ec45..ff0c67228 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -43,7 +43,7 @@ REQUIREMENTS = [
     "jsonschema>=2.5.1",
     "frozendict>=1",
     "unpaddedbase64>=1.1.0",
-    "canonicaljson>=1.3.0",
+    "canonicaljson>=1.4.0",
     # we use the type definitions added in signedjson 1.1.
     "signedjson>=1.1.0",
     "pynacl>=1.2.1",