diff --git a/.ruff.toml b/.ruff.toml
index 7a8331a..cccd6ed 100644
--- a/.ruff.toml
+++ b/.ruff.toml
@@ -1,6 +1,6 @@
 # The contents of this file is based on https://github.com/home-assistant/core/blob/dev/pyproject.toml
 
-target-version = "py310"
+target-version = "py39"
 
 select = [
     "B007", # Loop control variable {name} not used within loop body
diff --git a/wyoming-microsoft-tts/download.py b/wyoming-microsoft-tts/download.py
index 236e65c..f9c4971 100755
--- a/wyoming-microsoft-tts/download.py
+++ b/wyoming-microsoft-tts/download.py
@@ -2,7 +2,7 @@
 import json
 import logging
 from pathlib import Path
-from typing import Any
+from typing import Any, Union
 from urllib.parse import quote, urlsplit, urlunsplit
 from urllib.request import Request, urlopen
 
@@ -57,7 +57,7 @@ def transform_voices_files(response):
 
 
 def get_voices(
-    download_dir: str | Path,
+    download_dir: Union[str, Path],
     update_voices: bool = False,
     region: str = "westus",
     key: str = "",
@@ -94,7 +94,7 @@ def get_voices(
         return json.load(voices_file)
 
 
-def find_voice(name: str, download_dir: str | Path) -> dict[str, Any]:
+def find_voice(name: str, download_dir: Union[str, Path]) -> dict[str, Any]:
     """Look for the files for a voice.
 
     Returns: Dict of voice info