Hi, mpdecimal-4.0.0 has been released: https://www.bytereef.org/mpdecimal/changelog.html https://www.bytereef.org/mpdecimal/download.html The release has been tested on a compile farm for five months on the following platforms: x86_64, i386, aarch64, ppc64, ppc64le, chrp, sparc64, sparc32, mips64, mips32, risc-v, Wasm Tested compilers: gcc, clang, icc, icx, xlc, ibm-clang, cl.exe, clang-cl, mingw-gcc, CompCert, emscripten Distributors of CPython are strongly encouraged to build CPython --with-system-libmpdec (as most of them already do). Additionally, distributors of Python-11 and Python-12 are advised to revert the implementation of the z-format specifier in _decimal.c. It contains a memory leak for large decimals and does not support the "EG" types. mpdecimal-4.0.0 automatically supports the z-format specifier without patches to _decimal.c. The following patch cleanly reverts b0b836b20cb56c225874a4a39ef895f89ab2970f and applies to both Python-11 and Python-12: https://www.bytereef.org/contrib/0001-py12-revert-z-format-specifier.patch For the main branch, the following patches are advised: # As above: https://www.bytereef.org/contrib/0001-main-revert-z-format-specifier.patch # Implement a catch-all fallback for _all_ future format specifiers that # are _temporarily_ unsupported in mpdecimal. The fallback is clean and # is zero-cost for the general common case: https://www.bytereef.org/contrib/0002-main-fallback-to-pydecimal-format.patc... # Fix a deprecation warning that is incorrectly triggered for a fill # character that contains 'N': https://www.bytereef.org/contrib/0003-main-fix-deprecation-warning.patch All patches are "BSD-2-clause, Copyright (c) Stefan Krah", same as mpdecimal and Modules/_decimal/*. Finally, due to the nature of multiphase initialization, its current implementation in the main branch slows down the pi benchmark compared to 3.9 by: --enable-gil: 31% --disable-gil: 47% Stefan Krah