diff --git a/.github/workflows/bump-flake-lock-and-selfup.yml b/.github/workflows/bump-flake-lock-and-selfup.yml
new file mode 100644
index 0000000..799e246
--- /dev/null
+++ b/.github/workflows/bump-flake-lock-and-selfup.yml
@@ -0,0 +1,25 @@
+name: Bump flake.lock and related dependencies
+on:
+  pull_request:
+    paths:
+      - '.github/workflows/bump-flake-lock-and-selfup.yml'
+  schedule:
+    # At 10:17 JST on day-of-month 1 and on Monday.
+    # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#schedule
+    - cron: '17 1 1 * 1'
+  workflow_dispatch:
+
+jobs:
+  bump:
+    uses: kachick/selfup/.github/workflows/reusable-bump-flake-lock-and-selfup.yml@action-v1
+    if: (github.event.sender.login == 'kachick') || (github.event_name != 'pull_request')
+    with:
+      dry-run: ${{ github.event_name == 'pull_request' }}
+      optional-run: |
+        nix develop --command bash -c 'node --version | tr -d v' > .node-version
+        # https://stackoverflow.com/q/34807971
+        git update-index -q --really-refresh
+        git diff-index --quiet HEAD || git commit -m 'Update .node-version' .node-version
+    secrets:
+      APP_ID: ${{ secrets.APP_ID }}
+      APP_PRIVATE_KEY: ${{ secrets.APP_PRIVATE_KEY }}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b122433..bf59b77 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,7 +23,7 @@ jobs:
       - uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
       - uses: actions/setup-node@60edb5dd545a775178f52524783378180af0d1f8 # v4.0.2
         with:
-          node-version: '20.8.0' # selfup { "regex": "\\d[^']+", "script": "node --version | tr -d v" }
+          node-version-file: '.node-version'
           cache: npm
       - run: npm ci --ignore-scripts
       - run: npm run build
@@ -39,7 +39,7 @@ jobs:
           submodules: recursive
       - uses: actions/setup-node@60edb5dd545a775178f52524783378180af0d1f8 # v4.0.2
         with:
-          node-version: '20.8.0' # selfup { "regex": "\\d[^']+", "script": "node --version | tr -d v" }
+          node-version-file: '.node-version'
           cache: npm
       - run: npm ci --ignore-scripts
       - run: npm test
@@ -51,7 +51,7 @@ jobs:
       - uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
       - uses: actions/setup-node@60edb5dd545a775178f52524783378180af0d1f8 # v4.0.2
         with:
-          node-version: '20.8.0' # selfup { "regex": "\\d[^']+", "script": "node --version | tr -d v" }
+          node-version-file: '.node-version'
           cache: npm
       - run: npm ci --ignore-scripts
       - name: Typecheck
diff --git a/.github/workflows/merge-bot-pr.yml b/.github/workflows/merge-bot-pr.yml
index abaece6..23510e8 100644
--- a/.github/workflows/merge-bot-pr.yml
+++ b/.github/workflows/merge-bot-pr.yml
@@ -25,3 +25,18 @@ jobs:
         env:
           PR_URL: ${{github.event.pull_request.html_url}}
           GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+
+  # https://github.com/kachick/anylang-template/issues/51
+  selfup-runner:
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    if: ${{ github.actor == 'selfup-runner[bot]' }}
+    steps:
+      - name: Wait other jobs
+        uses: kachick/wait-other-jobs@v2
+        timeout-minutes: 20
+      - name: Approve and merge
+        run: gh pr review --approve "$PR_URL" && gh pr merge --auto --delete-branch --squash "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}