diff --git a/.github/workflows/python_build_ci.yml b/.github/workflows/python_build_ci.yml
index 71cfc926d..74ab30fd3 100644
--- a/.github/workflows/python_build_ci.yml
+++ b/.github/workflows/python_build_ci.yml
@@ -37,111 +37,145 @@ jobs:
           path: ./wheels/*.whl
 
 
-  package_linux_arm_1:
-    name: Python Package Linux ARM 1
-
+  # package_linux_arm_1:
+  #   name: Python Package Linux ARM 1
+
+  #   runs-on: ubuntu-24.04
+  #   env:
+  #     CI_ACTIVE : 1
+  #     TBB_INSTALL_DIR: /tmp/tbb_build
+
+  #   steps:
+  #     - uses: actions/checkout@v4
+  #     - uses: actions/setup-python@v5
+
+  #     - name: Set up QEMU
+  #       uses: docker/setup-qemu-action@v3
+  #       with:
+  #         platforms: all
+
+  #     - name: Install Dependencies
+  #       run: |
+  #         sudo apt-get install libtbb-dev libhwloc-dev libboost-program-options-dev
+  #         python3 -m pip install cibuildwheel>=2.22.0
+
+  #     - name: Build Python Wheels
+  #       env:
+  #         CIBW_ARCHS_LINUX: aarch64
+  #         CIBW_BUILD: cp3{9,10,11}-manylinux*
+  #       run: |
+  #         # run cmake to create pyproject.toml from pyproject.toml.in
+  #         cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=Off
+  #         rm -rf configure_python
+  #         python3 -m cibuildwheel --output-dir wheels
+
+  #     - uses: actions/upload-artifact@v4
+  #       with:
+  #         name: cibw-wheels-ubuntu-24.04-arm1
+  #         path: ./wheels/*.whl
+
+  # package_linux_arm_2:
+  #   name: Python Package Linux ARM 2
+
+  #   runs-on: ubuntu-24.04
+  #   env:
+  #     CI_ACTIVE : 1
+  #     TBB_INSTALL_DIR: /tmp/tbb_build
+
+  #   steps:
+  #     - uses: actions/checkout@v4
+  #     - uses: actions/setup-python@v5
+
+  #     - name: Set up QEMU
+  #       uses: docker/setup-qemu-action@v3
+  #       with:
+  #         platforms: all
+
+  #     - name: Install Dependencies
+  #       run: |
+  #         sudo apt-get install libtbb-dev libhwloc-dev libboost-program-options-dev
+  #         python3 -m pip install cibuildwheel>=2.22.0
+
+  #     - name: Build Python Wheels
+  #       env:
+  #         CIBW_ARCHS_LINUX: aarch64
+  #         CIBW_BUILD: cp3*-manylinux*
+  #         CIBW_PROJECT_REQUIRES_PYTHON: ">=3.12"
+  #       run: |
+  #         # run cmake to create pyproject.toml from pyproject.toml.in
+  #         cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=Off
+  #         rm -rf configure_python
+  #         python3 -m cibuildwheel --output-dir wheels
+
+  #     - uses: actions/upload-artifact@v4
+  #       with:
+  #         name: cibw-wheels-ubuntu-24.04-arm2
+  #         path: ./wheels/*.whl
+
+
+  # package_macos:
+  #   name: Python Package MacOS
+
+  #   runs-on: macos-latest
+  #   env:
+  #     CI_ACTIVE : 1
+  #     TBB_INSTALL_DIR: /tmp/tbb_build
+
+  #   steps:
+  #     - uses: actions/checkout@v4
+  #     - uses: actions/setup-python@v5
+
+  #     - name: Install Dependencies
+  #       run: |
+  #         brew install tbb boost pipx
+
+  #     - name: Build Python Wheels
+  #       env:
+  #         CIBW_ARCHS_MACOS: x86_64 arm64
+  #         CIBW_BUILD: cp3*-macos*
+  #         # TBB doesn't compile on older MacOS than 10.13
+  #         MACOSX_DEPLOYMENT_TARGET: 10.13
+  #       run: |
+  #         # run cmake to create pyproject.toml from pyproject.toml.in
+  #         cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=On
+  #         rm -rf configure_python
+  #         pipx run cibuildwheel --output-dir wheels
+
+  #     - uses: actions/upload-artifact@v4
+  #       with:
+  #         name: cibw-wheels-macos
+  #         path: ./wheels/*.whl
+
+
+  build_sdist:
+    name: Build source distribution
     runs-on: ubuntu-24.04
-    env:
-      CI_ACTIVE : 1
-      TBB_INSTALL_DIR: /tmp/tbb_build
-
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-        with:
-          platforms: all
 
-      - name: Install Dependencies
-        run: |
-          sudo apt-get install libtbb-dev libhwloc-dev libboost-program-options-dev
-          python3 -m pip install cibuildwheel>=2.22.0
-
-      - name: Build Python Wheels
-        env:
-          CIBW_ARCHS_LINUX: aarch64
-          CIBW_BUILD: cp3{9,10,11}-manylinux*
-        run: |
-          # run cmake to create pyproject.toml from pyproject.toml.in
-          cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=Off
-          rm -rf configure_python
-          python3 -m cibuildwheel --output-dir wheels
+      - name: Build sdist
+        run: pipx run build --sdist
 
       - uses: actions/upload-artifact@v4
         with:
-          name: cibw-wheels-ubuntu-24.04-arm1
-          path: ./wheels/*.whl
-
-  package_linux_arm_2:
-    name: Python Package Linux ARM 2
+          name: cibw-sdist
+          path: dist/*.tar.gz
 
+  upload_pypi:
+    needs: [package_linux_x86, build_sdist] # package_linux_arm_1, package_linux_arm_2, package_macos, build_sdist]
     runs-on: ubuntu-24.04
-    env:
-      CI_ACTIVE : 1
-      TBB_INSTALL_DIR: /tmp/tbb_build
-
+    environment: testpypi
+    permissions:
+      id-token: write
+    # if: github.event_name == 'release' && github.event.action == 'published'
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-        with:
-          platforms: all
-
-      - name: Install Dependencies
-        run: |
-          sudo apt-get install libtbb-dev libhwloc-dev libboost-program-options-dev
-          python3 -m pip install cibuildwheel>=2.22.0
-
-      - name: Build Python Wheels
-        env:
-          CIBW_ARCHS_LINUX: aarch64
-          CIBW_BUILD: cp3*-manylinux*
-          CIBW_PROJECT_REQUIRES_PYTHON: ">=3.12"
-        run: |
-          # run cmake to create pyproject.toml from pyproject.toml.in
-          cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=Off
-          rm -rf configure_python
-          python3 -m cibuildwheel --output-dir wheels
-
-      - uses: actions/upload-artifact@v4
+      - uses: actions/download-artifact@v4
         with:
-          name: cibw-wheels-ubuntu-24.04-arm2
-          path: ./wheels/*.whl
-
-
-  package_macos:
-    name: Python Package MacOS
-
-    runs-on: macos-latest
-    env:
-      CI_ACTIVE : 1
-      TBB_INSTALL_DIR: /tmp/tbb_build
-
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-
-      - name: Install Dependencies
-        run: |
-          brew install tbb boost pipx
+          # unpacks all CIBW artifacts into dist/
+          pattern: cibw-*
+          path: dist
+          merge-multiple: true
 
-      - name: Build Python Wheels
-        env:
-          CIBW_ARCHS_MACOS: x86_64 arm64
-          CIBW_BUILD: cp3*-macos*
-          # TBB doesn't compile on older MacOS than 10.13
-          MACOSX_DEPLOYMENT_TARGET: 10.13
-        run: |
-          # run cmake to create pyproject.toml from pyproject.toml.in
-          cmake -B configure_python --preset=minimal -DKAHYPAR_SETUP_PYTHON=On -DKAHYPAR_TBB_DIR=$TBB_INSTALL_DIR -DKAHYPAR_DISABLE_HWLOC=On
-          rm -rf configure_python
-          pipx run cibuildwheel --output-dir wheels
-
-      - uses: actions/upload-artifact@v4
+      - uses: pypa/gh-action-pypi-publish@release/v1
         with:
-          name: cibw-wheels-macos
-          path: ./wheels/*.whl
+          repository-url: https://test.pypi.org/legacy/