diff --git a/python/servo/testing_commands.py b/python/servo/testing_commands.py
index 3fad465277b..7bee7633f90 100644
--- a/python/servo/testing_commands.py
+++ b/python/servo/testing_commands.py
@@ -49,7 +49,7 @@ WEB_PLATFORM_TESTS_PATH = os.path.join("tests", "wpt", "web-platform-tests")
 SERVO_TESTS_PATH = os.path.join("tests", "wpt", "mozilla", "tests")
 
 CLANGFMT_CPP_DIRS = ["support/hololens/"]
-CLANGFMT_VERSION = "8"
+CLANGFMT_VERSION = "9"
 
 TEST_SUITES = OrderedDict([
     ("tidy", {"kwargs": {"all_files": False, "no_progress": False, "self_test": False,