Python Dev Notes

Each Python version uses a specific compiler version. In most cases, you should use the same compiler version for building python extensions.

Which Microsoft Visual C++ compiler to use with a specific Python version ?

Currently, ONNXRuntime only supports Visual C++ 2017. Therefore, Python 3.7 seems to be the best choice.

CPython 3.7 is distributed with a VC++ 2017 runtime. Unlike the earlier VC++ version, VC++ 2017 Runtime is binary backward compatible with VC++ 2015. Which means you could build your application with VC++ 2015 then run it with VC++ 2017 runtime.