diff -rupN a/tests/test_doi.py b/tests/test_doi.py
--- a/tests/test_doi.py	2019-12-29 01:16:09.000000000 +0000
+++ b/tests/test_doi.py	2026-03-31 00:56:26.570000000 +0000
@@ -1,7 +1,7 @@
 """Tests for `doi` package."""
 
 import os
-from pkg_resources import parse_version
+from packaging.version import parse
 
 from doi import (
     validate_doi, find_doi_in_text, __version__, pdf_to_doi,
@@ -11,7 +11,7 @@ from doi import (
 
 def test_valid_version() -> None:
     """Check that the package defines a valid __version__"""
-    assert parse_version(__version__) >= parse_version("0.1.0")
+    assert parse(__version__) >= parse("0.1.0")
 
 
 def test_validate_doi() -> None: