diff --git a/.github/workflows/clang-format.yml b/.github/workflows/clang-format.yml
index cca2eb7c..36388d68 100644
--- a/.github/workflows/clang-format.yml
+++ b/.github/workflows/clang-format.yml
@@ -5,14 +5,12 @@ on: [push]
 jobs:
   clang-format:
 
-    runs-on: ubuntu-20.04 # latest
+    runs-on: ubuntu-24.04 # latest
 
     steps:
     - name: Checkout Sources
-      uses: actions/checkout@v1
+      uses: actions/checkout@v4
 
     - name: clang-format lint
-      uses: DoozyX/clang-format-lint-action@v0.3.1
-      with:
-        # List of extensions to check
-        extensions: c,h
+      run: |
+        ./format-check.py
diff --git a/format-check.py b/format-check.py
new file mode 100755
index 00000000..b9e3520c
--- /dev/null
+++ b/format-check.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+import argparse
+import os
+from pathlib import Path
+import re
+from subprocess import list2cmdline, run
+from tempfile import NamedTemporaryFile
+
+CLANG_FORMAT_VERSION = '18.1.6'
+
+INCLUDE_REGEX = re.compile(
+    r'^(include|source|tests|verification)/.*\.(c|h|inl)$')
+EXCLUDE_REGEX = re.compile(r'^$')
+
+arg_parser = argparse.ArgumentParser(description="Check with clang-format")
+arg_parser.add_argument('-i', '--inplace-edit', action='store_true',
+                        help="Edit files inplace")
+args = arg_parser.parse_args()
+
+os.chdir(Path(__file__).parent)
+
+# create file containing list of all files to format
+filepaths_file = NamedTemporaryFile(delete=False)
+for dirpath, dirnames, filenames in os.walk('.'):
+    for filename in filenames:
+        # our regexes expect filepath to use forward slash
+        filepath = Path(dirpath, filename).as_posix()
+        if not INCLUDE_REGEX.match(filepath):
+            continue
+        if EXCLUDE_REGEX.match(filepath):
+            continue
+
+        filepaths_file.write(f"{filepath}\n".encode())
+filepaths_file.close()
+
+# use pipx to run clang-format from PyPI
+# this is a simple way to run the same clang-format version regardless of OS
+cmd = ['pipx', 'run', f'clang-format=={CLANG_FORMAT_VERSION}',
+       f'--files={filepaths_file.name}']
+if args.inplace_edit:
+    cmd += ['-i']
+else:
+    cmd += ['--Werror', '--dry-run']
+
+print(f"{Path.cwd()}$ {list2cmdline(cmd)}")
+if run(cmd).returncode:
+    exit(1)
diff --git a/format-check.sh b/format-check.sh
deleted file mode 100755
index 48eb6e35..00000000
--- a/format-check.sh
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-
-if [[ -z $CLANG_FORMAT ]] ; then
-    CLANG_FORMAT=clang-format
-fi
-
-if NOT type $CLANG_FORMAT 2> /dev/null ; then
-    echo "No appropriate clang-format found."
-    exit 1
-fi
-
-FAIL=0
-SOURCE_FILES=`find bin source include tests -type f \( -name '*.h' -o -name '*.c' \)`
-for i in $SOURCE_FILES
-do
-    $CLANG_FORMAT -output-replacements-xml $i | grep -c "<replacement " > /dev/null
-    if [ $? -ne 1 ]
-    then
-        echo "$i failed clang-format check."
-        FAIL=1
-    fi
-done
-
-exit $FAIL
diff --git a/source/packets.c b/source/packets.c
index 1170bcca..d208a9de 100644
--- a/source/packets.c
+++ b/source/packets.c
@@ -235,9 +235,8 @@ int aws_mqtt_packet_connect_encode(struct aws_byte_buf *buf, const struct aws_mq
     }
 
     /* Write connect flags [MQTT-3.1.2.3] */
-    uint8_t connect_flags = (uint8_t)(
-        packet->clean_session << 1 | packet->has_will << 2 | packet->will_qos << 3 | packet->will_retain << 5 |
-        packet->has_password << 6 | packet->has_username << 7);
+    uint8_t connect_flags = (uint8_t)(packet->clean_session << 1 | packet->has_will << 2 | packet->will_qos << 3 |
+                                      packet->will_retain << 5 | packet->has_password << 6 | packet->has_username << 7);
 
     if (!aws_byte_buf_write_u8(buf, connect_flags)) {
         return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
diff --git a/tests/v5/mqtt5_client_tests.c b/tests/v5/mqtt5_client_tests.c
index 267f5725..fe869ecc 100644
--- a/tests/v5/mqtt5_client_tests.c
+++ b/tests/v5/mqtt5_client_tests.c
@@ -6013,8 +6013,10 @@ struct outbound_alias_publish {
 
 #define DEFINE_OUTBOUND_ALIAS_PUBLISH(topic_suffix, desired_alias, expected_alias_index, reused)                       \
     {                                                                                                                  \
-        .topic = aws_byte_cursor_from_string(s_topic_##topic_suffix), .topic_alias = desired_alias,                    \
-        .expected_alias_id = expected_alias_index, .expected_reuse = reused,                                           \
+        .topic = aws_byte_cursor_from_string(s_topic_##topic_suffix),                                                  \
+        .topic_alias = desired_alias,                                                                                  \
+        .expected_alias_id = expected_alias_index,                                                                     \
+        .expected_reuse = reused,                                                                                      \
     }
 
 static void s_outbound_alias_publish_completion_fn(
diff --git a/tests/v5/mqtt5_topic_alias_tests.c b/tests/v5/mqtt5_topic_alias_tests.c
index 52fe6dfd..e9513b39 100644
--- a/tests/v5/mqtt5_topic_alias_tests.c
+++ b/tests/v5/mqtt5_topic_alias_tests.c
@@ -411,7 +411,8 @@ struct lru_test_operation {
 
 #define DEFINE_LRU_TEST_OPERATION(topic_type, alias_index, reused)                                                     \
     {                                                                                                                  \
-        .topic = aws_byte_cursor_from_string(s_topic_##topic_type), .expected_alias_id = alias_index,                  \
+        .topic = aws_byte_cursor_from_string(s_topic_##topic_type),                                                    \
+        .expected_alias_id = alias_index,                                                                              \
         .expected_reuse = reused,                                                                                      \
     }