diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 83a1a98..7f08b76 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -22,6 +22,8 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
+        # requirements.txt omits setuptools (pip-compile); setuptools<82 needed for pkg_resources (devpi-server)
+        python -m pip install 'setuptools<82'
         python -m pip install -r requirements.txt
         python -m pip install --no-deps -e .
         if [ "${{ matrix.python-version }}" != "3.13" ]; then  # workaround for TheKevJames/coveralls-python#523
diff --git a/core-requirements.txt b/core-requirements.txt
index d8d84ee..3373585 100644
--- a/core-requirements.txt
+++ b/core-requirements.txt
@@ -1,7 +1,7 @@
 devpi-plumber>=0.2.14
-setuptools
+setuptools<82  # setuptools 82 drops pkg_resources
 wheel
-wheel-filename
+wheel-filename<2  # wheel-filename 2 breaks imports of InvalidFilenameError, parse_wheel_filename
 wheel-inspect>=1.6.0
 pip>=1.5.3
 junit-xml>=1.9  # First version to support to_xml_report_file