When Microsoft announced DirectX 12 in 2014, it did not reveal any compatibility information. The new version of DirectX was announced at a time when Windows 8 was the latest operating system; Windows 10 was released in 2015.
We assumed back then that Microsoft would limit DirectX artificially to Windows 8 or the upcoming version of Windows which we assumed would be Windows 9.
Microsoft revealed at the end of 2014 that Windows 10 would indeed ship with DirectX 12 support. Rumors suggested that the new version would not be made available to earlier versions of Windows, and a Microsoft support article confirmed that. Windows 7 systems were stuck with DirectX 11.0 and 11.1, Windows 8.1 with Direct X 11.1 and 11.2
Four years later, in early 2019, Microsoft suddenly announced that DirectX 12 support would be coming to select games on Windows 7. Game companies urged Microsoft to bring DirectX 12 to Windows 7 to make use of advanced capabilities and reduce development costs at the same time.
Microsoft began to port the Direct3D 12 runtime as a response to Windows 7. Blizzard, maker of World of Warcraft and other games, was the first company to support a DirectX 12 game on Windows 7. World of Warcraft gamers could run the game using DirectX 12 to benefit from better framerates and other improvements.
Options to bring DirectX 12 games to Windows 7 devices were limited initially but work with several game studios — none is mentioned in particular except Blizzard — continued after the initial announcement.
Microsoft released a new development guidance in August 2019 to allow game developers to run their DirectX 12 games on Windows 7.
“To better support game developers at larger scales, we are publishing the following resources to allow game developers to run their DirectX 12 games on Windows 7.”
Developers can check out the Porting D3D12 games to Windows 7 guide to get started. The guide is divided into several chapters. It begins with a list of files and drivers that are needed to set up a development system and test machines. Other chapters reveal how to get DirectX 12 games up and ready on Windows 7 PCs, give optimization tips and release suggestions.