diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c619985..27ff873 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,8 +42,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.12"]
-        runs-on: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.10", "3.13"]
+        runs-on: [ubuntu-latest] #, macos-latest, windows-latest]
 
         include:
           - python-version: pypy-3.10
@@ -68,6 +68,6 @@ jobs:
           --durations=20
 
       - name: Upload coverage report
-        uses: codecov/codecov-action@v4.3.0
+        uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6c7760e..92689b8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,9 +3,3 @@ cmake_minimum_required(VERSION 3.15...3.26)
 set(SKBUILD_PROJECT_NAME pscpy)
 
 project(${SKBUILD_PROJECT_NAME} LANGUAGES CXX)
-
-set(PYBIND11_FINDPYTHON ON)
-find_package(pybind11 CONFIG REQUIRED)
-
-pybind11_add_module(_core MODULE src/main.cpp)
-install(TARGETS _core DESTINATION ${SKBUILD_PROJECT_NAME})
diff --git a/src/main.cpp b/src/main.cpp
deleted file mode 100644
index d570cd0..0000000
--- a/src/main.cpp
+++ /dev/null
@@ -1,27 +0,0 @@
-#include <pybind11/pybind11.h>
-
-int add(int i, int j) { return i + j; }
-
-namespace py = pybind11;
-
-PYBIND11_MODULE(_core, m) {
-  m.doc() = R"pbdoc(
-      Pybind11 example plugin
-      -----------------------
-      .. currentmodule:: python_example
-      .. autosummary::
-         :toctree: _generate
-         add
-         subtract
-  )pbdoc";
-
-  m.def("add", &add, R"pbdoc(
-      Add two numbers
-      Some other explanation about the add function.
-  )pbdoc");
-
-  m.def("subtract", [](int i, int j) { return i - j; }, R"pbdoc(
-      Subtract two numbers
-      Some other explanation about the subtract function.
-  )pbdoc");
-}
diff --git a/src/pscpy/adios2py/__init__.py b/src/pscpy/adios2py/__init__.py
index e8dc201..97fef40 100644
--- a/src/pscpy/adios2py/__init__.py
+++ b/src/pscpy/adios2py/__init__.py
@@ -54,7 +54,7 @@ def _name(self) -> str:
     def _dtype(self) -> np.dtype[Any]:
         self._assert_not_closed()
 
-        return np.dtype(adios2.type_adios_to_numpy(self._var.type()))
+        return np.dtype(adios2.type_adios_to_numpy(self._var.type()))  # type: ignore[no-any-return]
 
     def __getitem__(self, args: SupportsInt | slice | tuple[SupportsInt | slice, ...]) -> NDArray[Any]:
         self._assert_not_closed()
diff --git a/src/pscpy/psc.py b/src/pscpy/psc.py
index b6d4f0d..2db072a 100644
--- a/src/pscpy/psc.py
+++ b/src/pscpy/psc.py
@@ -37,7 +37,7 @@ def __init__(self, file: File, length: ArrayLike | None = None, corner: ArrayLik
         self.z = self._get_coord(2)
 
     def _get_coord(self, coord_idx: int) -> NDArray[np.floating[Any]]:
-        return np.linspace(  # type: ignore[no-any-return]
+        return np.linspace(
             start=self.corner[coord_idx],
             stop=self.corner[coord_idx] + self.length[coord_idx],
             num=self.gdims[coord_idx],
diff --git a/src/pscpy/pscadios2.py b/src/pscpy/pscadios2.py
index bcfb5fc..70e599a 100644
--- a/src/pscpy/pscadios2.py
+++ b/src/pscpy/pscadios2.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import io
 import os
 import pathlib
 from typing import Any, Iterable, Protocol, SupportsInt
@@ -25,6 +24,7 @@
 )
 from xarray.core import indexing
 from xarray.core.datatree import DataTree
+from xarray.core.types import ReadBuffer
 from xarray.core.utils import Frozen, FrozenDict
 
 from .adios2py import File, Variable
@@ -149,7 +149,7 @@ def psc_open_dataset(
     length: ArrayLike | None = None,
     corner: ArrayLike | None = None,
 ) -> xarray.Dataset:
-    filename = _normalize_path(filename_or_obj)  # type: ignore[no-untyped-call]
+    filename = _normalize_path(filename_or_obj)
     store = PscAdios2Store.open(filename, species_names, length=length, corner=corner)
 
     data_vars, attrs = store.load()  # type: ignore[no-untyped-call]
@@ -167,13 +167,12 @@ class PscAdios2BackendEntrypoint(BackendEntrypoint):
     @override
     def open_dataset(
         self,
-        filename_or_obj: str | os.PathLike[Any] | io.BufferedIOBase | AbstractDataStore,
+        filename_or_obj: str | os.PathLike[Any] | ReadBuffer[Any] | AbstractDataStore,
         *,
         drop_variables: str | Iterable[str] | None = None,
         length: ArrayLike | None = None,
         corner: ArrayLike | None = None,
         species_names: Iterable[str] | None = None,  # e.g. ['e', 'i']; FIXME should be readable from file
-        **kwargs: Any,
     ) -> xarray.Dataset:
         if not isinstance(filename_or_obj, (str, os.PathLike)):
             raise NotImplementedError()
@@ -190,14 +189,14 @@ def open_dataset(
         )
 
     @override
-    def guess_can_open(self, filename_or_obj: str | os.PathLike[Any] | io.BufferedIOBase | AbstractDataStore) -> bool:
+    def guess_can_open(self, filename_or_obj: str | os.PathLike[Any] | ReadBuffer[Any] | AbstractDataStore) -> bool:
         if isinstance(filename_or_obj, (str, os.PathLike)):
             ext = pathlib.Path(filename_or_obj).suffix
             return ext in {".bp"}
         return False
 
     @override
-    def open_datatree(self, filename_or_obj: str | os.PathLike[Any] | io.BufferedIOBase | AbstractDataStore, **kwargs: Any) -> DataTree[Any]:
+    def open_datatree(self, filename_or_obj: str | os.PathLike[Any] | ReadBuffer[Any] | AbstractDataStore, **kwargs: Any) -> DataTree:
         raise NotImplementedError()
 
 
diff --git a/tests/test_compiled.py b/tests/test_compiled.py
deleted file mode 100644
index 845d50a..0000000
--- a/tests/test_compiled.py
+++ /dev/null
@@ -1,11 +0,0 @@
-from __future__ import annotations
-
-import pscpy._core as m
-
-
-def test_add():
-    assert m.add(2, 3) == 5
-
-
-def test_subtract():
-    assert m.subtract(7, 5) == 2