This is the first release candidate for pybind11 2.6.0. Please see the new features in the changelog, such as revamped CMake and setuptools support, keyword and positional argument support, and a long list of features, fixes, and improvements. Full Python 3.9 support and enhanced C++20 support.

Known issues:

• py::module_ direct construction provisionally deprecated
• Removing registered types can cause a segfault - old issue exposed by recent test additions; fix incoming
• On Python 3.9.0 and macOS, pybind11 may segfault when closing the interpreter after running the test suite