UPDATE - August 22, 2013: AMD send out word that the Radeon HD 7000 series will be fully DirectX 11.2 capable after a driver update.
TPU reports AMD confirmed that its "Southern Islands" and "Sea Islands" GPUs, branded under the Radeon HD 7000 and Radeon HD 8000 (OEM) series, will not fully support the upcoming DirectX 11.2. This new API will be introduced in October when Microsoft issues the Windows 8.1 update.
Exclusive with the upcoming Windows 8.1 operating system, the Direct3D component of DirectX 11.2 introduces a handful of revolutionary consumer 3D features, such as "D3D tiled resources," which is analogous to OpenGL mega-textures; HLSL shader linking, frame-buffer scaling, etc.
In an interview with German publication c't Magazin, AMD engineer Laylah Mah pointed out that a feedback routine Microsoft deployed in the final specification of DirectX 11.2 turned out different from the one AMD anticipated. Mah stressed that the incompatibility is not at the level of the hardware, but the driver.
It's unknown if NVIDIA's GeForce GTX 7xx series fully supports DirectX 11.2.