diff --git a/spoolman/database/spool.py b/spoolman/database/spool.py
index c797438..1681a9b 100644
--- a/spoolman/database/spool.py
+++ b/spoolman/database/spool.py
@@ -1,6 +1,6 @@
 """Helper functions for interacting with spool database objects."""
 
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from typing import Optional
 
 import sqlalchemy
@@ -15,7 +15,7 @@ from spoolman.math import weight_from_length
 
 def utc_timezone_naive(dt: datetime) -> datetime:
     """Convert a datetime object to UTC and remove timezone info."""
-    return dt.astimezone(UTC).replace(tzinfo=None)
+    return dt.astimezone(tz=timezone.utc).replace(tzinfo=None)
 
 
 async def create(
diff --git a/spoolman/main.py b/spoolman/main.py
index e7c4b25..d54a056 100644
--- a/spoolman/main.py
+++ b/spoolman/main.py
@@ -5,6 +5,7 @@ import os
 import subprocess
 from logging.handlers import TimedRotatingFileHandler
 from pathlib import Path
+from typing import Union
 
 import uvicorn
 from fastapi import FastAPI
@@ -45,7 +46,7 @@ class SinglePageApplication(StaticFiles):
         """Construct."""
         super().__init__(directory=directory, packages=None, html=True, check_dir=True)
 
-    def lookup_path(self, path: str) -> tuple[str, os.stat_result | None]:
+    def lookup_path(self, path: str) -> tuple[str, Union[os.stat_result, None]]:
         """Return index.html if the requested file cannot be found."""
         full_path, stat_result = super().lookup_path(path)