Hey, for the details on the D3D 11.1 and DXGI 1.2 API's functionality limitations with the platform update for windows 7, this page covers the specifics:
The platform update basically brings support for most of the API changes, however it won't allow you to use the D3D 11.1 feature level. That's to say you can use the 11.1 API, with interfaces such as an ID3D11Device1 with a d3d_feature_level_11_0, but you can't create an ID3D11Device1 with a d3d_feature_level_11_1. At least not a hardware device.
The reason for that is due to Windows 7 only supporting WDDM 1.1 drivers, so D3D 11.1 / DXGI 1.2 features that require WDDM 1.2 driver functionality cannot work. You can use 11_1 feature level with a software (i.e. reference) device, since a software device doesn't interact with any WDDM drivers. More info here: http://msdn.microsoft.com/en-us/library/windows/desktop/ff476329(v=vs.85).aspx#D3D_FEATURE_LEVEL_11_1
I doubt this will change, short of MS backporting WDDM 1.2 to windows 7 (which they most probably won't). Until the OS supports WDDM 1.2, there's no way for vendors (NV or AMD) to provide full D3D11.1 drivers for windows 7.
The short version is you can use the D3D11.1 and DXGI 1.2 APIs on windows 7, but you can't use some of their features that're exclusive to D3D11.1 /DXGI1.2, as detailed in the first link.
Edited by backstep, 06 September 2013 - 09:35 AM.