diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c9b17e9..38015da 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,9 +14,10 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         # pick lower and upper versions only
-        python-version: ["3.8", "3.12"]
+        python-version: ["3.9", "3.12"]
 
     steps:
       - uses: actions/checkout@v4
@@ -53,9 +54,9 @@ jobs:
           pytest -v swn --doctest-modules
 
       - name: Run tests with older flopy and other packages
-        if: matrix.python-version == '3.8'
+        if: matrix.python-version == '3.9'
         run: |
-          pip install "flopy<3.5" "pandas<2.0" "shapely<2.0"
+          pip install "flopy<3.5" "pandas<2.0" "geopandas<1.0" "shapely<2.0" "numpy<2.0"
           pytest -v -n2 --cov --cov-append
 
       - name: Upload coverage reports to Codecov
diff --git a/README.md b/README.md
index f407ce6..099df8d 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ A Python package to create and analyze surface water networks.
 
 ## Python packages
 
-Python 3.8+ is required.
+Python 3.9+ is required.
 
 ### Required
 
diff --git a/pyproject.toml b/pyproject.toml
index df20b1d..1155285 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,7 @@ classifiers = [
     "Programming Language :: Python :: 3 :: Only",
     "Topic :: Scientific/Engineering :: Hydrology",
 ]
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
     "geopandas >=0.9",
     "packaging",