Problem with specs of GPU

I am buying the R7-250x for my home PC and I am seeing something strange Asus, XFX, PowerColor are stating that the GPU supports Dx11.2 and Gigabyte says its Dx11.1 and sapphire says its dx12 and Amd spec sheet says Dx 12. So can anybody really say whats he real DX version of this GPU or its that Manufacturers can modify DX version on their Own