diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 7f31c3e1..5ee2b15e 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15"]
 
     steps:
       - uses: actions/checkout@v5
@@ -36,3 +36,69 @@ jobs:
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: coverage.lcov
+
+  format:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v5
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - name: Install black
+        run: |
+          python -m pip install --upgrade pip
+          pip install "black~=26.0"
+      - name: Check formatting with black
+        run: |
+          black --check --diff .
+
+  docs:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v5
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          # same version as the ReadTheDocs build (.readthedocs.yaml)
+          python-version: "3.11"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[docs]"
+      - name: Build documentation, treating warnings as errors
+        run: |
+          sphinx-build -W --keep-going -b html doc doc/_build/html
+
+  package:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v5
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - name: Build wheel
+        run: |
+          python -m pip install --upgrade pip build
+          python -m build --wheel --outdir dist .
+      - name: Install wheel in a clean environment
+        run: |
+          python -m venv "$RUNNER_TEMP/wheelenv"
+          "$RUNNER_TEMP/wheelenv/bin/pip" install dist/*.whl
+      - name: Import every module from the installed wheel
+        # run outside the checkout, in isolated mode, so that the source tree cannot be imported
+        working-directory: ${{ runner.temp }}
+        run: |
+          "$RUNNER_TEMP/wheelenv/bin/python" -I -c '
+          import importlib, pkgutil, fairgraph
+          print(fairgraph.__file__, fairgraph.__version__)
+          for m in pkgutil.walk_packages(fairgraph.__path__, "fairgraph."):
+              importlib.import_module(m.name)
+          '
diff --git a/doc/contributing.rst b/doc/contributing.rst
index cf8b94b5..7c6e910a 100644
--- a/doc/contributing.rst
+++ b/doc/contributing.rst
@@ -197,6 +197,9 @@ Coding standards and style
 All code should conform as much as possible to `PEP 8`_.
 We use black_ to auto-format the code, with a line length of 119 characters.
 Please run ``black`` before making a commit.
+Continuous integration checks the formatting with::
+
+    $ black --check .
 
 As a basic check of code quality, run::
 
@@ -231,6 +234,12 @@ To build the documentation::
 
 Then open `_build/html/index.html` in your browser.
 
+Continuous integration builds the documentation with warnings treated as errors,
+so before submitting changes, check that the following runs without warnings::
+
+    $ cd doc
+    $ sphinx-build -W --keep-going -b html . _build/html
+
 Committing your changes
 -----------------------
 
diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 8bf82261..36fa272d 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -23,6 +23,9 @@ New features
 Changes in behaviour
 --------------------
 
+- fairgraph now requires Python 3.10 or later, as Python 3.9 has reached end of life.
+  It is tested with Python 3.10 to 3.15.
+
 - Leading and trailing whitespace is now removed from text properties before they are saved
   Text loaded from the Knowledge Graph is left as it is until saved, so saving a fetched object corrects
   any untrimmed text that is stored.
diff --git a/pyproject.toml b/pyproject.toml
index f03f8110..ba24f645 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ readme = "README.md"
 authors = [
     { name="Andrew P. Davison", email="andrew.davison@cnrs.fr" }
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = "Apache-2.0"
 classifiers = [
     "Development Status :: 4 - Beta",
@@ -60,4 +60,4 @@ include = ["fairgraph*"]
 
 [tool.black]
 line-length = 119
-target-version = ["py39"]
+target-version = ["py310"]