diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
index f1fc58c..4342a71 100644
--- a/.github/workflows/pip.yml
+++ b/.github/workflows/pip.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['3.11', '3.12', '3.13']
+        python-version: ['3.8', '3.11', '3.12', '3.13']
         numpy: ['"numpy<2.0"', "numpy"]
         os: [ubuntu-latest]
         pytest: [pytest]
diff --git a/scipy_doctest/util.py b/scipy_doctest/util.py
index 8baf064..85a35c8 100644
--- a/scipy_doctest/util.py
+++ b/scipy_doctest/util.py
@@ -10,7 +10,7 @@
 import inspect
 from contextlib import contextmanager
 
-from typing import Sequence
+from typing import Sequence, Union
 
 from importlib.metadata import version as get_version, PackageNotFoundError
 from packaging.requirements import Requirement
@@ -259,7 +259,7 @@ def get_public_objects(module, skiplist=None):
     return (items, names), failures
 
 
-def is_req_satisfied(req_strs: str | Sequence[str]) -> bool:
+def is_req_satisfied(req_strs: Union[str, Sequence[str]]) -> bool:
     """ Check if all PEP 508-compliant requirement(s) are satisfied or not.
     """
     req_strs = [req_strs] if isinstance(req_strs, str) else req_strs