What I meant is basically when you install a game or whatever, there are like requirements of specific OS builds.
Besides the security issues, I think DX11 will remain mainstream for quite some time now, it's harder to develop for DX12 from what I heard and readOnce January 14, 2020 hits, you will begin to have massive holes in your OS. Much like what happened with Win XP, hackers aren't going to try and exploit new holes for the last few months leading up to the EOL as they don't want MS to know about those holes and have them patched. Right now just about every game that is DirectX12 requires Win 10. MS added support for only a couple DX12 games in Win 7.