diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 37398498..35572f1c 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -20,7 +20,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
-        python-version: ['3.12', '3.11'] # ['3.8', '3.x']
+        python-version: ['3.12', '3.11', '3.10'] # ['3.8', '3.x']
         exclude:
           # tests with ubuntu-latest, python latest
           # are executed by build_docs.yaml
@@ -29,7 +29,7 @@ jobs:
 
     steps:
     - name: Checkout source
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         persist-credentials: false
 
diff --git a/pyproject.toml b/pyproject.toml
index 8b71f6ac..89d98144 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [build-system]
 requires = [
     "setuptools >= 61",
-    #'tomli; python_version < "3.11"',
+    'tomli; python_version < "3.11"',
 ]
 build-backend = "setuptools.build_meta"
 
@@ -23,7 +23,7 @@ classifiers = [
     "Programming Language :: Python :: 3 :: Only",
     "Topic :: Scientific/Engineering :: Hydrology",
 ]
-requires-python = ">=3.11"
+requires-python = ">=3.10"
 dependencies = [
     "geopandas",
     "gis-utils",