If you write an app based on Direct3D 9 or 11, it usually just works on any supported version of Windows.
I once wrote an app that uses OpenGL 4.0 (this one: https://github.com/Const-me/GL3Windows), and it only worked on half of my PCs. To make it work everywhere, I had to downgrade to OpenGL 3.0, and also implement S3 texture decompression on the CPU.
If you write an app based on Direct3D 9 or 11, it usually just works on any supported version of Windows.
I once wrote an app that uses OpenGL 4.0 (this one: https://github.com/Const-me/GL3Windows), and it only worked on half of my PCs. To make it work everywhere, I had to downgrade to OpenGL 3.0, and also implement S3 texture decompression on the CPU.