diff --git a/backend/audit.py b/backend/audit.py
index cfb8a44..42d615d 100644
--- a/backend/audit.py
+++ b/backend/audit.py
@@ -10,7 +10,7 @@ Format: JSON lines (one JSON object per line) for easy parsing.
 import json
 import logging
 import os
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from pathlib import Path
 
 logger = logging.getLogger("obsigate.audit")
@@ -54,7 +54,7 @@ def log_file_save(
 ):
     """Log a file save (PUT) operation."""
     _write_entry({
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": "file_save",
         "username": username,
         "ip": ip or "unknown",
@@ -72,7 +72,7 @@ def log_file_delete(
 ):
     """Log a file delete operation."""
     _write_entry({
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": "file_delete",
         "username": username,
         "ip": ip or "unknown",
@@ -88,7 +88,7 @@ def log_config_change(
 ):
     """Log a configuration change."""
     _write_entry({
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": "config_change",
         "username": username,
         "ip": ip or "unknown",
@@ -99,7 +99,7 @@ def log_config_change(
 def log_vault_add(username: str, vault_name: str, vault_path: str, ip: str | None = None):
     """Log a vault addition."""
     _write_entry({
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": "vault_add",
         "username": username,
         "ip": ip or "unknown",
@@ -111,7 +111,7 @@ def log_vault_add(username: str, vault_name: str, vault_path: str, ip: str | Non
 def log_vault_remove(username: str, vault_name: str, ip: str | None = None):
     """Log a vault removal."""
     _write_entry({
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": "vault_remove",
         "username": username,
         "ip": ip or "unknown",
@@ -136,7 +136,7 @@ def log_coffre_event(
     (coffre:<slug>/<nom>), des identifiants et des codes de résultat.
     """
     entry = {
-        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "timestamp": datetime.now(UTC).isoformat(),
         "action": action,
         "username": username,
         "ip": ip or "unknown",