diff --git a/.github/workflows/build-wheel.yml b/.github/workflows/build-wheel.yml
index ffcab41734d..9b702a8c17e 100644
--- a/.github/workflows/build-wheel.yml
+++ b/.github/workflows/build-wheel.yml
@@ -34,6 +34,8 @@ jobs:
           - "3.13"
           - "3.14"
           - "3.14t"
+          - "3.15"
+          - "3.15t"
     name: py${{ matrix.python-version }}
     runs-on: ${{ (inputs.host-platform == 'linux-64' && 'linux-amd64-cpu8') ||
                  (inputs.host-platform == 'linux-aarch64' && 'linux-arm64-cpu8') ||
@@ -162,12 +164,20 @@ jobs:
           cuda-version: ${{ inputs.cuda-version }}
 
       - name: Build cuda.bindings wheel
-        uses: pypa/cibuildwheel@8d2b08b68458a16aeb24b64e68a09ab1c8e82084  # v3.4.1
+        uses: pypa/cibuildwheel@54327ab9d35de03b359ac25c97de9417d94639c0  # v4.0.0rc1
         with:
           package-dir: ./cuda_bindings/
           output-dir: ${{ env.CUDA_BINDINGS_ARTIFACTS_DIR }}
         env:
           CIBW_BUILD: ${{ env.CIBW_BUILD }}
+          # Allow CPython pre-release builds (currently 3.15 / 3.15t). This is a
+          # no-op for stable Python versions because CIBW_BUILD still filters
+          # the target version.
+          CIBW_ENABLE: cpython-prerelease
+          # v4.0 made delvewheel the default Windows repair command. We rely
+          # on cuda.pathfinder for runtime DLL discovery, so preserve the
+          # previous behaviour (no automatic DLL bundling) for now.
+          CIBW_REPAIR_WHEEL_COMMAND_WINDOWS: ""
           # CIBW mounts the host filesystem under /host
           CIBW_ENVIRONMENT_LINUX: >
             CUDA_PATH=/host/${{ env.CUDA_PATH }}
@@ -226,12 +236,20 @@ jobs:
           if-no-files-found: error
 
       - name: Build cuda.core wheel
-        uses: pypa/cibuildwheel@8d2b08b68458a16aeb24b64e68a09ab1c8e82084  # v3.4.1
+        uses: pypa/cibuildwheel@54327ab9d35de03b359ac25c97de9417d94639c0  # v4.0.0rc1
         with:
           package-dir: ./cuda_core/
           output-dir: ${{ env.CUDA_CORE_ARTIFACTS_DIR }}
         env:
           CIBW_BUILD: ${{ env.CIBW_BUILD }}
+          # Allow CPython pre-release builds (currently 3.15 / 3.15t). This is a
+          # no-op for stable Python versions because CIBW_BUILD still filters
+          # the target version.
+          CIBW_ENABLE: cpython-prerelease
+          # v4.0 made delvewheel the default Windows repair command. We rely
+          # on cuda.pathfinder for runtime DLL discovery, so preserve the
+          # previous behaviour (no automatic DLL bundling) for now.
+          CIBW_REPAIR_WHEEL_COMMAND_WINDOWS: ""
           # CIBW mounts the host filesystem under /host
           CIBW_ENVIRONMENT_LINUX: >
             CUDA_PATH=/host/${{ env.CUDA_PATH }}
@@ -327,6 +345,7 @@ jobs:
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6.2.0
         with:
           python-version: ${{ matrix.python-version }}
+          allow-prereleases: true
 
       - name: verify free-threaded build
         if: endsWith(matrix.python-version, 't')
@@ -411,12 +430,20 @@ jobs:
           rmdir $OLD_BASENAME
 
       - name: Build cuda.core wheel
-        uses: pypa/cibuildwheel@8d2b08b68458a16aeb24b64e68a09ab1c8e82084  # v3.4.1
+        uses: pypa/cibuildwheel@54327ab9d35de03b359ac25c97de9417d94639c0  # v4.0.0rc1
         with:
           package-dir: ./cuda_core/
           output-dir: ${{ env.CUDA_CORE_ARTIFACTS_DIR }}
         env:
           CIBW_BUILD: ${{ env.CIBW_BUILD }}
+          # Allow CPython pre-release builds (currently 3.15 / 3.15t). This is a
+          # no-op for stable Python versions because CIBW_BUILD still filters
+          # the target version.
+          CIBW_ENABLE: cpython-prerelease
+          # v4.0 made delvewheel the default Windows repair command. We rely
+          # on cuda.pathfinder for runtime DLL discovery, so preserve the
+          # previous behaviour (no automatic DLL bundling) for now.
+          CIBW_REPAIR_WHEEL_COMMAND_WINDOWS: ""
           # CIBW mounts the host filesystem under /host
           CIBW_ENVIRONMENT_LINUX: >
             CUDA_PATH=/host/${{ env.CUDA_PATH }}
diff --git a/.github/workflows/test-wheel-linux.yml b/.github/workflows/test-wheel-linux.yml
index 725eda307f9..c442b3703e1 100644
--- a/.github/workflows/test-wheel-linux.yml
+++ b/.github/workflows/test-wheel-linux.yml
@@ -257,6 +257,7 @@ jobs:
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6.2.0
         with:
           python-version: ${{ matrix.PY_VER }}
+          allow-prereleases: true
         env:
           # we use self-hosted runners on which setup-python behaves weirdly (Python include can't be found)...
           AGENT_TOOLSDIRECTORY: "/opt/hostedtoolcache"
diff --git a/ci/test-matrix.yml b/ci/test-matrix.yml
index 35f02847ed7..896e9140dd7 100644
--- a/ci/test-matrix.yml
+++ b/ci/test-matrix.yml
@@ -36,6 +36,8 @@ linux:
     - { ARCH: 'amd64', PY_VER: '3.14t', CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 't4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'amd64', PY_VER: '3.14t', CUDA_VER: '13.0.2', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'amd64', PY_VER: '3.14t', CUDA_VER: '13.2.1', LOCAL_CTK: '1', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'amd64', PY_VER: '3.15',  CUDA_VER: '13.2.1', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
+    - { ARCH: 'amd64', PY_VER: '3.15t', CUDA_VER: '13.2.1', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
     # linux-aarch64
     - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '12.9.1', LOCAL_CTK: '1', GPU: 'a100',       GPU_COUNT: '1', DRIVER: 'latest' }
     - { ARCH: 'arm64', PY_VER: '3.10',  CUDA_VER: '13.0.2', LOCAL_CTK: '0', GPU: 'l4',         GPU_COUNT: '1', DRIVER: 'latest' }
diff --git a/cuda_bindings/pyproject.toml b/cuda_bindings/pyproject.toml
index bac72f5b9be..539e7f2fac0 100644
--- a/cuda_bindings/pyproject.toml
+++ b/cuda_bindings/pyproject.toml
@@ -44,7 +44,6 @@ all = [
 test = [
     "cython>=3.2,<3.3",
     "setuptools>=77.0.0",
-    "matplotlib>=3.5.0",  # Required by isoFDModelling_test.py
     "numpy>=1.21.1",
     "pytest>=6.2.4",
     "pytest-benchmark>=3.4.1",
diff --git a/cuda_core/pyproject.toml b/cuda_core/pyproject.toml
index d5a4b5fd29c..c1510f8d06b 100644
--- a/cuda_core/pyproject.toml
+++ b/cuda_core/pyproject.toml
@@ -58,7 +58,7 @@ cu12 = ["cuda-bindings[all]==12.*"]
 cu13 = ["cuda-bindings[all]==13.*"]
 
 [dependency-groups]
-test = ["cython>=3.2,<3.3", "setuptools", "pytest>=6.2.4", "pytest-benchmark", "pytest-randomly", "pytest-repeat", "pytest-rerunfailures", "cloudpickle", "psutil", "cffi"]
+test = ["cython>=3.2,<3.3", "setuptools", "pytest>=6.2.4", "pytest-benchmark", "pytest-randomly", "pytest-repeat", "pytest-rerunfailures", "cloudpickle", "psutil"]
 ml-dtypes = ["ml-dtypes>=0.5.4,<0.6.0"]
 test-cu12 = [ {include-group = "ml-dtypes" }, {include-group = "test" }, "cupy-cuda12x; python_version < '3.14'", "cuda-toolkit[cudart]==12.*"]  # runtime headers needed by CuPy
 test-cu13 = [ {include-group = "ml-dtypes" }, {include-group = "test" }, "cupy-cuda13x; python_version < '3.14'", "cuda-toolkit[cudart]==13.*"]  # runtime headers needed by CuPy