diff --git a/.github/workflows/minimal-test.yml b/.github/workflows/minimal-test.yml
index 021f871..c582b5a 100644
--- a/.github/workflows/minimal-test.yml
+++ b/.github/workflows/minimal-test.yml
@@ -18,10 +18,10 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install poetry
         run: pip install poetry
-      - name: Force the chosen flask version
-        run: poetry add flask==${{ matrix.flask-version }}
       - name: Install requirements
         run: poetry install
+      - name: Force the chosen flask version
+        run: pip install flask==${{ matrix.flask-version }}
       - name: Test package
         run: poetry run test
       - name: Test package
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fda0012..ec2460c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,10 +18,10 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install poetry
         run: pip install poetry
-      - name: Force the chosen flask version
-        run: poetry add flask==${{ matrix.flask-version }}
       - name: Install requirements
         run: poetry install
+      - name: Force the chosen flask version
+        run: pip install flask==${{ matrix.flask-version }}
       - name: Run unit tests
         run: poetry run test
       - name: Run doctests