diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ff4788b..7a6237c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,11 +13,11 @@ jobs:
     strategy:
       matrix:
         python-version: ["3.10"]
-        toxenv: [black, flake8, mypy]
+        toxenv: [black, ruff, mypy]
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
@@ -34,7 +34,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "pypy-3.9"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
         optional-deps: [true]
         with-libs: [true]
         include:
@@ -66,24 +66,24 @@ jobs:
     - name: Remove xz
       if: runner.os == 'Linux' && !matrix.optional-deps
       run: while which xz; do sudo rm $(which xz); done
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: python -m pip install tox
     - name: Test
-      run: tox -e py
+      run: tox run -e ${{ matrix.python-version }}
       if: matrix.with-libs
     - name: Test without python-isal and python-zlib-ng
-      run: tox -e no-libs
+      run: tox run -e no-libs
       if: true && !matrix.with-libs
     - name: Test with zstandard
       if: matrix.with-zstandard
-      run: tox -e zstd
+      run: tox run -e zstd
     - name: Upload coverage report
       uses: codecov/codecov-action@v3
 
@@ -93,11 +93,11 @@ jobs:
     needs: [lint, test]
     if: startsWith(github.ref, 'refs/tags')
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0  # required for setuptools_scm
     - name: Set up Python
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v6
       with:
         python-version: "3.10"
     - name: Make distributions
diff --git a/README.rst b/README.rst
index 2e5c268..da5ff17 100644
--- a/README.rst
+++ b/README.rst
@@ -185,7 +185,7 @@ Changelog
 development version
 ~~~~~~~~~~~~~~~~~~~
 
-* Dropped support for Python 3.8
+* Dropped support for Python 3.8 and 3.9
 * Started supporting Python 3.13
 
 v2.0.2 (2024-06-12)
diff --git a/pyproject.toml b/pyproject.toml
index c0f5bc2..afbf201 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,7 +15,7 @@ classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Programming Language :: Python :: 3"
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 dynamic = ["version"]
 dependencies = [
     'isal>=1.6.1; platform.machine == "x86_64" or platform.machine == "AMD64" or platform.machine == "aarch64"',
@@ -34,3 +34,12 @@ write_to = "src/xopen/_version.py"
 
 [tool.pytest.ini_options]
 addopts = "--strict-markers"
+
+[tool.coverage.run]
+branch = true
+
+[tool.coverage.report]
+exclude_also = [
+    "def __repr__",
+    "@overload",
+]
diff --git a/src/xopen/__init__.py b/src/xopen/__init__.py
index 89f5137..1348ea9 100644
--- a/src/xopen/__init__.py
+++ b/src/xopen/__init__.py
@@ -72,12 +72,6 @@
 
 try:
     import fcntl
-
-    # fcntl.F_SETPIPE_SZ will be available in python 3.10.
-    # https://github.com/python/cpython/pull/21921
-    # If not available: set it to the correct value for known platforms.
-    if not hasattr(fcntl, "F_SETPIPE_SZ") and sys.platform == "linux":
-        setattr(fcntl, "F_SETPIPE_SZ", 1031)
 except ImportError:
     fcntl = None  # type: ignore
 
diff --git a/tox.ini b/tox.ini
deleted file mode 100644
index f1ef44a..0000000
--- a/tox.ini
+++ /dev/null
@@ -1,55 +0,0 @@
-[tox]
-envlist = black,flake8,mypy,py39,py310,py311,py312,py313,pypy3
-isolated_build = True
-
-[testenv]
-deps =
-    pytest
-    pytest-timeout
-    coverage
-setenv =
-    PYTHONDEVMODE = 1
-    PYTHONWARNDEFAULTENCODING = 1
-commands =
-    coverage run --branch --source=xopen,tests -m pytest -v --doctest-modules tests
-    coverage report
-    coverage xml
-    coverage html
-
-[testenv:zstd]
-deps =
-    {[testenv]deps}
-    zstandard
-
-[testenv:no-libs]
-commands=
-    pip uninstall -y isal zlib-ng
-    {[testenv]commands}
-
-[testenv:black]
-basepython = python3.10
-deps = black==22.3.0
-skip_install = true
-commands = black --check src/ tests/
-
-[testenv:flake8]
-basepython = python3.10
-deps = flake8
-commands = flake8 src/ tests/
-skip_install = true
-
-[testenv:mypy]
-basepython = python3.10
-deps = mypy
-commands = mypy src/
-
-[flake8]
-max-line-length = 99
-max-complexity = 10
-extend_ignore = E731
-
-[coverage:report]
-exclude_lines =
-    pragma: no cover
-    def __repr__
-    @overload
diff --git a/tox.toml b/tox.toml
new file mode 100644
index 0000000..3ee996d
--- /dev/null
+++ b/tox.toml
@@ -0,0 +1,43 @@
+env_list = ["black", "ruff", "mypy", "3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
+
+[env_run_base]
+default_base_python = "3.10"
+deps = [
+    "pytest",
+    "pytest-timeout",
+    "coverage",
+]
+set_env = { PYTHONDEVMODE = "1", PYTHONWARNDEFAULTENCODING = "1" }
+commands = [
+    ["coverage", "run", "--source=xopen,tests", "-m", "pytest", "-v", "--doctest-modules", "tests"],
+    ["coverage", "report"],
+    ["coverage", "xml"],
+    ["coverage", "html"],
+]
+
+[env.zstd]
+deps = [
+    "{[env_run_base]deps}",
+    "zstandard",
+]
+
+[env.no-libs]
+deps = ["{[env_run_base]deps}", "pip"]
+commands = [
+    ["{env_python}", "-m", "pip", "uninstall", "-y", "isal", "zlib-ng"],
+    { replace = "ref", of = ["env_run_base", "commands"], extend = true },
+]
+
+[env.black]
+deps = ["black==22.3.0"]
+skip_install = true
+commands = [["black", "--check", "src/", "tests/"]]
+
+[env.ruff]
+deps = ["ruff"]
+commands = [["ruff", "check", "src/", "tests/"]]
+skip_install = true
+
+[env.mypy]
+deps = ["mypy"]
+commands = [["mypy", "src/"]]