New features:

• Publish binary wheel packages on PyPI with support for multiple operating systems (Linux, macOS, Windows), processor architectures (AMD64, ARM64), MPI implementations (MPICH, Open MPI, and their ABI-compatible derivatives), and Python implementations (CPython, PyPy).
• Add support for the MPI 5.0 standard.
  • MPI handle serialization with integral values.
  • Fixed-size Fortran LOGICAL datatypes.
  • Query ABI version/info and Fortran ABI info.
• MPI.Datatype.Create_contiguous now uses BigMPI's approach when using MPI implementations that do not yet support the MPI 4.0 large-count APIs.
• Add support for MPI.FLOAT16_T and MPI.BFLOAT16_T datatypes. These datatypes are not yet standard but available as extensions in MPI implementations.
• Add MPI.Status.tomemory to expose the status contents as a memoryview object.

Enhancements:

• Support (opt-in via MPI4PY_BUILD_PYSABI) for building with Py_LIMITED_API under Python 3.10+ (requires Cython 3.1+).
• Support (opt-in via MPI4PY_BUILD_MPIABI) for building with the MPI 5.0 standard ABI and the MPICH or Open MPI legacy ABIs. The MPI extension module will be able to dynamically link at runtime with older versions (down to the MPI 3.0 standard) of the MPI implementation used at compile time. Only available on Linux, macOS, and Windows.
• Support a buffersize parameter in the MPIPoolExecutor.map() and MPIPoolExecutor.starmap() methods to limit the number of pending tasks.
• Improve ownership management of DLPack capsules.
• Reimplement MPI DLL search path on Windows.
• Minor fixes to typing stubs and documentation.

Backward-incompatible changes:

• Python 3.8+ is required.
• The MPI.Exception class is now a heap type.
• The types of the MPI.BOTTOM, MPI.IN_PLACE, and MPI.BUFFER_AUTOMATIC are no longer subclasses of int.