macosx11 installer requires macOS 11+ for CPython 3.8 while macosx11 installer for CPython 3.9+ only requires macOS 10.9+ on x86_64.
macosx11 installer requires macOS 11+ for CPython 3.8 while macosx11 installer for CPython 3.9+ only requires macOS 10.9+ on x86_64.