diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
deleted file mode 100644
index 5982ccb..0000000
--- a/.github/workflows/ci.yml
+++ /dev/null
@@ -1,88 +0,0 @@
-name: CI
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-jobs:
-  checks:
-    name: Checks
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Setup Python 3.8
-        uses: actions/setup-python@v2
-        with:
-          python-version: 3.8
-      - name: Use pip cache
-        uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip
-          key: pip-${{ hashFiles('**/requirements*.txt') }}
-          restore-keys: |
-            pip-
-      - name: Install development tools
-        run: |
-          pip install -r requirements.dev.txt
-          pip install build twine nox
-      - name: Tests
-          python3 -m pytest
-      - name: Check distribution build
-        run: |
-          python3 -m build
-          python3 -m twine check dist/*
-
-  # Disabling for now.
-  # docs:
-  #   name: Build documentation
-  #   runs-on: ubuntu-latest
-  #   steps:
-  #     - name: Checkout
-  #       uses: actions/checkout@v2
-  #     - name: Setup Python 3.8
-  #       uses: actions/setup-python@v2
-  #       with:
-  #         python-version: 3.8
-  #     - name: Use pip cache
-  #       uses: actions/cache@v2
-  #       with:
-  #         path: ~/.cache/pip
-  #         key: pip-${{ hashFiles('**/requirements*.txt') }}
-  #         restore-keys: |
-  #           pip-
-  #     - name: Install nox
-  #       run: pip install nox
-  #     - name: Build docs
-  #       run: nox -s build_docs
-  #     - name: Publish to GitHub Pages
-  #       if: github.event_name == 'push'
-  #       run: |
-  #         # Create empty gh-pages branch
-  #         git checkout --orphan gh-pages
-
-  #         # Remove files other than docs
-  #         git rm -rf .
-  #         rm -rf .nox
-  #         find . -name __pycache__ | xargs rm -r
-
-  #         # Move docs to root
-  #         mv docs/html/* ./
-  #         rm -r docs
-
-  #         # Prevent GitHub from assuming that this is a Jekyll site
-  #         touch .nojekyll
-
-  #         git config user.name "${GITHUB_ACTOR}"
-  #         git config user.email "${GITHUB_ACTOR}@users.noreply.github.com"
-
-  #         git add .
-  #         git commit --allow-empty -m "Update docs"
-
-  #         git push --force origin gh-pages
-
-  #         # Restore the original working tree by checking out the
-  #         # commit that triggered the workflow.
-  #         # This restores requirements.txt so that @actions/cache
-  #         # can use it for determining the cache key.
-  #         git checkout ${GITHUB_SHA}
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..af0cf96
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,25 @@
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.10", "3.11"]
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+      - name: Display Python version
+        run: python -c "import sys; print(sys.version)"
+      - name: Install dependencies
+        run: python -m pip install -r requirements.txt
+      - name: Run tests
+        run: python -m pytest -vs
diff --git a/requirements.dev.in b/requirements.dev.in
deleted file mode 100644
index 2ae764b..0000000
--- a/requirements.dev.in
+++ /dev/null
@@ -1,6 +0,0 @@
-black==21.9b0 # This should be kept in sync with the version in .pre-commit-config.yaml
-isort==5.9.3 # This should be kept in sync with the version in .pre-commit-config.yaml
-pylint
-pytest
-msprime
-tskit
diff --git a/requirements.dev.txt b/requirements.dev.txt
deleted file mode 100644
index aedf1e7..0000000
--- a/requirements.dev.txt
+++ /dev/null
@@ -1,93 +0,0 @@
-#
-# This file is autogenerated by pip-compile with python 3.8
-# To update, run:
-#
-#    pip-compile requirements.dev.in
-#
-astroid==2.9.3
-    # via pylint
-attrs==21.4.0
-    # via
-    #   demes
-    #   jsonschema
-    #   pytest
-black==21.9b0
-    # via -r requirements.dev.in
-click==8.0.4
-    # via black
-demes==0.2.1
-    # via msprime
-importlib-resources==5.4.0
-    # via jsonschema
-iniconfig==1.1.1
-    # via pytest
-isort==5.9.3
-    # via
-    #   -r requirements.dev.in
-    #   pylint
-jsonschema==4.4.0
-    # via tskit
-lazy-object-proxy==1.7.1
-    # via astroid
-mccabe==0.6.1
-    # via pylint
-msprime==1.1.1
-    # via -r requirements.dev.in
-mypy-extensions==0.4.3
-    # via black
-newick==1.3.2
-    # via msprime
-numpy==1.22.2
-    # via
-    #   msprime
-    #   tskit
-packaging==21.3
-    # via pytest
-pathspec==0.9.0
-    # via black
-platformdirs==2.5.1
-    # via
-    #   black
-    #   pylint
-pluggy==1.0.0
-    # via pytest
-py==1.11.0
-    # via pytest
-pylint==2.12.2
-    # via -r requirements.dev.in
-pyparsing==3.0.7
-    # via packaging
-pyrsistent==0.18.1
-    # via jsonschema
-pytest==7.0.1
-    # via -r requirements.dev.in
-regex==2022.1.18
-    # via black
-ruamel-yaml==0.17.21
-    # via demes
-ruamel-yaml-clib==0.2.6
-    # via ruamel-yaml
-svgwrite==1.4.1
-    # via tskit
-toml==0.10.2
-    # via pylint
-tomli==1.2.3
-    # via
-    #   black
-    #   pytest
-tskit==0.4.1
-    # via
-    #   -r requirements.dev.in
-    #   msprime
-typing-extensions==4.1.1
-    # via
-    #   astroid
-    #   black
-    #   pylint
-wrapt==1.13.3
-    # via astroid
-zipp==3.7.0
-    # via importlib-resources
-
-# The following packages are considered to be unsafe in a requirements file:
-# setuptools
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..553f70f
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+black
+pytest
+msprime
+tskit
+numba