Hi back, It seems like "config.struct_size = sizeof(PyConfig);" syntax is "not really liked". I don't see any traction to provide a stable ABI for embedded Python. The consensus is more towards: "it doesn't work and we don't want to bother with false promises" (nor add code for that). Since Lukasz is supposed to tag 3.8.0rc1 today, I propose to remove anything related to "stable API" or "stable ABI" from the PEP 587 right now. I wrote two PRs to remove struct_size: * CPython: https://github.com/python/cpython/pull/16500 * PEP 587: https://github.com/python/peps/pull/1185 Later, if we decide to start proving a stable ABI for embedded Python, we can still add a "version" or "struct_size" field to PyConfig later (for example in Python 3.9). Victor