Previously, *mincnt* was inclusive with no *C* provided but exclusive when *C* is provided.

It is now inclusive of *mincnt* in both cases.

``matplotlib.mpl_toolkits`` is now an implicit namespace package

Following the deprecation of ``pkg_resources.declare_namespace`` in ``setuptools`` 67.3.0,

``matplotlib.mpl_toolkits`` is now implemented as an implicit namespace, following

`PEP 420<https://peps.python.org/pep-0420/>`_.

As a consequence using ``pip`` to install a version of Matplotlib >= 3.8 on top

of a version of Matplotlib < 3.8 (e.g. via ``pip install --local`` or

``python -m venv --system-site-packages ...``) will fail because the old

``matplotlib.mpl_toolkits`` files will be found whereas the newer files will be

found for all other modules. This will result in errors due to the version

mismatch.

To avoid this issue you need to avoid having multiple versions of Matplotlib

in different entries of ``sys.path``. Either uninstall Matplotlib

at the system level or use a more isolated virtual environment.