That's a guru3D piece acknowledging your linked TPU news as source which is again referencing this HotHardware article, which does not mention DX11.1 at all. That's something TPU "invented" or just assumed from the HD7000 name and added to the story. The guy in the video they have there is actually saying the Trinity graphics has "second generation DX11 graphics", which basically means the NI generation which also fits with the VLIW4 shader architecture. It does not say DX11.1 or third generation or something like that.
And Anandtech just speculates about DX11.1 while flatly saying the slides only mention DX11 without the ".1".