diff --git a/.github/workflows/python.yaml b/.github/workflows/python.yaml
index 21cae53..0085bd3 100644
--- a/.github/workflows/python.yaml
+++ b/.github/workflows/python.yaml
@@ -25,14 +25,19 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.8", "3.9", "3.10", "3.11"]
-        # PyTorch does not support Python 3.11 on non-Linux platforms
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        # PyTorch now fully supports Python =<3.11
         # see: https://github.com/pytorch/pytorch/issues/86566
+        #
+        # PyTorch does not support Python 3.12 (all platforms)
+        # see: https://github.com/pytorch/pytorch/issues/110436
         exclude:
+          - os: ubuntu-latest
+            python-version: "3.12"
           - os: macos-latest
-            python-version: "3.11"
+            python-version: "3.12"
           - os: windows-latest
-            python-version: "3.11"
+            python-version: "3.12"
 
     defaults:
       run:
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index e87e98d..0fe531b 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 ci:
-    skip: [mypy]
+  skip: [mypy]
 
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
@@ -59,10 +59,3 @@ repos:
     hooks:
       - id: black
         stages: [commit]
-
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.8.0
-    hooks:
-      - id: mypy
-        additional_dependencies: [types-all]
-        exclude: 'test/conftest.py'
diff --git a/pyproject.toml b/pyproject.toml
index b932220..8ef3613 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,10 +34,9 @@ disallow_untyped_defs = true
 warn_redundant_casts = true
 warn_unreachable = true
 warn_unused_ignores = true
-exclude = '''
-  (?x)
-  ^test?s/conftest.py$
-'''
+exclude = '''(?x)(
+  test/conftest.py
+)'''
 
 
 [tool.coverage.run]
diff --git a/test/test_grad/test_hessian.py b/test/test_grad/test_hessian.py
index 8d9fe12..abc0c90 100644
--- a/test/test_grad/test_hessian.py
+++ b/test/test_grad/test_hessian.py
@@ -41,7 +41,7 @@ def test_fail() -> None:
     param = {"a1": numbers}
 
     # differentiable variable is not a tensor
-    with pytest.raises(RuntimeError):
+    with pytest.raises(ValueError):
         hessian(dftd3, (numbers, positions, param), argnums=2)
 
 
diff --git a/test/test_model/test_reference.py b/test/test_model/test_reference.py
index 05a55ab..99a6148 100644
--- a/test/test_model/test_reference.py
+++ b/test/test_model/test_reference.py
@@ -15,14 +15,15 @@
 """
 Test the reference.
 """
-from typing import Union
+from typing import Optional, Union
+from unittest.mock import patch
 
 import pytest
 import torch
 from tad_mctc.convert import str_to_device
 
 from tad_dftd3 import reference
-from tad_dftd3.typing import DD
+from tad_dftd3.typing import DD, Any, Tensor, TypedDict
 
 from ..conftest import DEVICE
 
@@ -37,8 +38,12 @@ def test_reference_dtype(dtype: torch.dtype) -> None:
 
 @pytest.mark.parametrize("dtype", [torch.float16, None])
 def test_reference_dtype_both(dtype: Union[torch.dtype, None]) -> None:
+    class DDNone(TypedDict):
+        device: torch.device
+        dtype: Optional[torch.dtype]
+
     dev = torch.device("cpu")
-    dd = {"device": dev, "dtype": dtype}
+    dd: DDNone = {"device": dev, "dtype": dtype}
     ref = reference.Reference(device=dev).to(**dd)
     assert ref.dtype == torch.tensor(1.0, dtype=dtype).dtype
 
@@ -63,6 +68,38 @@ def test_reference_device(device_str: str, device_str2: str) -> None:
         ref.device = device
 
 
+def test_reference_different_devices() -> None:
+    # Custom Tensor class with overridable device property
+    class MockTensor(Tensor):
+        @property
+        def device(self) -> Any:
+            return self._device
+
+        @device.setter
+        def device(self, value: Any) -> None:
+            self._device = value
+
+    # Custom mock functions
+    def mock_load_cn(*_: Any, **__: Any) -> Tensor:
+        tensor = MockTensor([1, 2, 3])
+        tensor.device = torch.device("cpu")
+        return tensor
+
+    def mock_load_c6(*_: Any, **__: Any) -> Tensor:
+        tensor = MockTensor([4, 5, 6])
+        tensor.device = torch.device("cuda")
+        return tensor
+
+    with patch("tad_dftd3.reference._load_cn", new=mock_load_cn):
+        with patch("tad_dftd3.reference._load_c6", new=mock_load_c6):
+            with pytest.raises(RuntimeError) as exc:
+                # Assuming the device is not explicitly passed, so it picks
+                # from _load_cn and _load_c6
+                reference.Reference()
+
+            assert "All tensors must be on the same device!" in str(exc.value)
+
+
 def test_reference_fail() -> None:
     c6 = reference._load_c6()  # pylint: disable=protected-access