diff --git a/mnemon/__init__.py b/mnemon/__init__.py
index dfe230c..f7570f2 100644
--- a/mnemon/__init__.py
+++ b/mnemon/__init__.py
@@ -20,7 +20,7 @@
 import subprocess
 import threading
 import time
-from datetime import datetime
+from datetime import datetime, timezone
 from pathlib import Path
 from typing import Any
 
@@ -247,7 +247,7 @@ def _remember_and_index(self, text: str, **kwargs) -> str | None:
                     idx = {}
             idx.setdefault("ids", {})
             idx["ids"][iid] = {
-                "ts": datetime.now(datetime.UTC).isoformat(),
+                "ts": datetime.now(timezone.utc).isoformat(),
                 "text_snippet": text[:80],
                 "store": self._store,
                 "session": self._session_id,
diff --git a/pyproject.toml b/pyproject.toml
index eeac034..a3d6fd1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -42,7 +42,7 @@ target-version = "py311"
 
 [tool.ruff.lint]
 select = ["E", "F", "I", "UP", "B"]
-ignore = ["E501"]
+ignore = ["E501", "UP017"]
 
 [tool.coverage.run]
 source = ["mnemon"]