diff --git a/.github/workflows/ci-testing.yml b/.github/workflows/ci-testing.yml
index b732cb4..a5a12e3 100644
--- a/.github/workflows/ci-testing.yml
+++ b/.github/workflows/ci-testing.yml
@@ -24,11 +24,19 @@ jobs:
       uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python-version }}
+        check-latest: true
+        cache: "pip"
+        cache-dependency-path: pyproject.toml
+    - name: Install Poetry
+      uses: snok/install-poetry@v1.1.6
+      with:
+        version: 1.1.4  # Specify the Poetry version
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
         python -m pip install flake8 pytest
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        poetry install
+
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names
diff --git a/pyproject.toml b/pyproject.toml
index 0de7ae6..114ecd7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,7 +11,7 @@ authors = [
     {name = "Raoul Collenteur", email = "raoul.collenteur@uni-graz.at"}
 ]
 license = { file = "LICENSE" }
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
     "numpy >= 1.16",
     "xarray >= 0.18.0",