diff --git a/pyproject.toml b/pyproject.toml
index a9630d6..43219b8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,11 +4,12 @@ build-backend = 'setuptools.build_meta'
 
 [project]
 name = 'whippersnappy'
-version = '2.0.0'
+version = '2.1.0-dev'
 description = 'A package to plot and capture FastSurfer and FreeSurfer-style surface overlays.'
 readme = 'README.md'
-license = {file = 'LICENSE'}
-requires-python = '>=3.9'
+license = 'MIT'
+license-files = ['LICENSE']
+requires-python = '>=3.10'
 authors = [
     {name = 'Martin Reuter', email = 'martin.reuter@dzne.de'},
 ]
@@ -31,7 +32,6 @@ classifiers = [
     'Programming Language :: Python :: 3.12',
     'Programming Language :: Python :: 3.13',
     'Natural Language :: English',
-    'License :: OSI Approved :: MIT License',
     'Intended Audience :: Science/Research',
 ]
 dependencies = [
diff --git a/whippersnappy/_config.py b/whippersnappy/_config.py
index 6617445..1437dab 100644
--- a/whippersnappy/_config.py
+++ b/whippersnappy/_config.py
@@ -3,14 +3,15 @@
 import platform
 import re
 import sys
+from collections.abc import Callable
 from functools import partial
 from importlib.metadata import requires, version
-from typing import IO, Callable, Optional
+from typing import IO
 
 import psutil
 
 
-def sys_info(fid: Optional[IO] = None, developer: bool = False):
+def sys_info(fid: IO | None = None, developer: bool = False):
     """Print the system information for debugging.
 
     Parameters