Windows 10 Anniversary Update (version 1607) includes WDDM 2.1, which supports Shader Model 6.0 (mandatory for feature levels 12_0 and 12_1),[44] and DXGI 1.5 which supports HDR10 - a 10-bit high dynamic range, wide gamut format[45] defined by ITU-T Rec. 2100/Rec.2020 - and variable refresh rates.[46]