diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9233b90d1a..c89e2b3420 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -39,165 +39,6 @@ on:
     types: ["opened", "reopened", "synchronize"]
 
 jobs:
-  java:
-    name: Java CI
-    runs-on: ubuntu-latest
-    env:
-      MY_VAR: "PATH"
-    strategy:
-      matrix:
-        java-version: ["8", "11", "17", "21"]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up JDK ${{ matrix.java-version }}
-        uses: actions/setup-java@v4
-        with:
-          java-version: ${{ matrix.java-version }}
-          distribution: "temurin"
-      - name: Set up Python3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Setup tmate session
-        uses: mxschmitt/action-tmate@v3
-      - name: Install bazel
-        run: ./ci/run_ci.sh install_bazel
-      - name: Install python
-        run: ./ci/run_ci.sh install_python
-      - name: Install pyfury
-        run: ./ci/run_ci.sh install_pyfury
-      - name: Run CI with Maven
-        run: ./ci/run_ci.sh java${{ matrix.java-version }}
-  openj9:
-    name: Openj9 Java CI
-    runs-on: ubuntu-latest
-    env:
-      MY_VAR: "PATH"
-    strategy:
-      matrix:
-        # String in openj9 1.8 share byte array by offset, fury doesn't allow it.
-        java-version: ["21"]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up JDK ${{ matrix.java-version }}
-        uses: actions/setup-java@v4
-        with:
-          java-version: ${{ matrix.java-version }}
-          distribution: "adopt-openj9"
-      - name: Set up Python3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Install bazel
-        run: ./ci/run_ci.sh install_bazel
-      - name: Install python
-        run: ./ci/run_ci.sh install_python
-      - name: Install pyfury
-        run: ./ci/run_ci.sh install_pyfury
-      - name: Run CI with Maven
-        run: ./ci/run_ci.sh java${{ matrix.java-version }}
-  graalvm:
-    name: GraalVM CI
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        java-version: ["17", "21", "22"]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: graalvm/setup-graalvm@v1
-        with:
-          java-version: ${{ matrix.java-version }}
-          distribution: "graalvm"
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          native-image-job-reports: "true"
-      - name: Set up Python3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Build native image and run
-        run: ./ci/run_ci.sh graalvm_test
-
-  scala:
-    name: Scala CI
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up JDK8
-        uses: actions/setup-java@v4
-        with:
-          java-version: 11
-          distribution: "temurin"
-      - name: Install fury java
-        run: cd java && mvn -T10 --no-transfer-progress clean install -DskipTests && cd -
-      - name: Test
-        run: |
-          sudo apt-get update
-          sudo apt-get install apt-transport-https curl gnupg -yqq
-          echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" | sudo tee /etc/apt/sources.list.d/sbt.list
-          echo "deb https://repo.scala-sbt.org/scalasbt/debian /" | sudo tee /etc/apt/sources.list.d/sbt_old.list
-          curl -sL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x2EE0EA64E40A89B84B2DF73499E82A75642AC823" | sudo -H gpg --no-default-keyring --keyring gnupg-ring:/etc/apt/trusted.gpg.d/scalasbt-release.gpg --import
-          sudo chmod 644 /etc/apt/trusted.gpg.d/scalasbt-release.gpg
-          sudo apt-get update
-          sudo apt-get install sbt
-          # Avoid sbt download jackson-databind error
-          rm -rf /home/runner/.m2/repository/com/fasterxml/jackson/
-          cd scala && sbt +test && cd -
-
-  integration_tests:
-    name: Integration Tests
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up JDK8
-        uses: actions/setup-java@v4
-        with:
-          java-version: 8
-          distribution: "temurin"
-      - name: Run CI
-        run: ./ci/run_ci.sh integration_tests
-
-  javascript:
-    name: JavaScript CI
-    strategy:
-      matrix:
-        node-version: [14.x, 16.x, 18.x, 20.x]
-        os: [ubuntu-latest, macos-13, windows-2022]
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v4
-      - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v4
-        with:
-          node-version: ${{ matrix.node-version }}
-      - name: Upgrade npm
-        run: npm install -g npm@8
-      # node-gyp needs to use python and relies on the distutils module.
-      # The distutils module has been removed starting from python 3.12
-      # (see https://docs.python.org/3.10/library/distutils.html). Some
-      # OS (such as macos -latest) uses python3.12 by default, so python 3.8
-      # is used here to avoid this problem.
-      - name: Set up Python3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Run CI with NodeJS
-        run: python ./ci/run_ci.py javascript
-
-  rust:
-    name: Rust CI
-    strategy:
-      matrix:
-        os: [ubuntu-latest, macos-13, macos-14] # macos-13: x86, macos-14: arm64
-    runs-on: ${{ matrix.os }}
-    timeout-minutes: 45
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Python 3.11
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.11
-      - name: Run Rust CI
-        run: python ./ci/run_ci.py rust
 
   cpp:
     name: C++ CI
@@ -213,67 +54,3 @@ jobs:
           python-version: 3.11
       - name: Run C++ CI with Bazel
         run: python ./ci/run_ci.py cpp
-  python:
-    name: Python CI
-    # Fix python 3.6 install issue, see
-    # https://github.com/rwth-i6/returnn/commit/38ecab17d781c4b74db6a174c8097187380b4ddc
-    runs-on: ubuntu-20.04
-    strategy:
-      matrix:
-        python-version: [3.7, 3.12]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
-        with:
-          python-version: ${{ matrix.python-version }}
-      - name: Install bazel
-        run: ./ci/run_ci.sh install_bazel
-      - name: Run Python CI
-        run: ./ci/run_ci.sh python
-
-  go:
-    name: Golang CI
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        go-version: ["1.13", "1.18"]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Setup Go ${{ matrix.go-version }}
-        uses: actions/setup-go@v4
-        with:
-          go-version: ${{ matrix.go-version }}
-      - name: Display Go version
-        run: go version
-      - name: Set up Python3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Install bazel
-        run: ./ci/run_ci.sh install_bazel
-      - name: Install python
-        run: ./ci/run_ci.sh install_python
-      - name: Install pyfury
-        run: ./ci/run_ci.sh install_pyfury
-      - name: Run Golang CI
-        run: ./ci/run_ci.sh go
-
-  lint:
-    name: Code Style Check
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up JDK ${{ matrix.java-version }}
-        uses: actions/setup-java@v4
-        with:
-          java-version: 21
-          distribution: "oracle"
-      - name: Check License Header
-        uses: korandoru/hawkeye@v3
-      - name: Set up Python 3.8
-        uses: actions/setup-python@v5
-        with:
-          python-version: 3.8
-      - name: Check code style
-        run: ./ci/run_ci.sh format