For Win32 desktops apps targeting Windows Vista - Windows 8.1, Direct3D 11.x and XAudio 2.7 is perfectly valid.
You have to continue to use the legacy DirectSetup to deploy XAudio 2.7 even on Windows 8.x, so I recommend using the refreshed version
rather than the one that came with the legacy DirectX SDK, which you can trim down per the instructions on MSDN
. Really XAudio down-level support is the one situation where you have to stick with using the legacy DirectX SDK. For Windows Store apps, Windows phone 8, and Xbox One you can count on XAudio 2.8, but you can't really effectively switch between XAudio 2.7 and XAudio 2.8 at runtime. See this blog post
I would recommend not using any other components in the legacy DirectX SDK such as D3DX (even D3DX11) if you can avoid it, which for Direct3D 11.x you can as detailed in this blog post