http://www.imgtec.com/News/Release/index.asp?NewsID=666
But the press release said that all Series6 GPUs will support OpenGL 4.x which includes tessellation and other capabilities that are also part of DX11 and otherwise exceeds a basic DX10 design. As you point out, if they're supporting DX11, they might as well go DX11.1 for those GPUs that require it. But if all Series6 GPUs already support OpenGL 4.x, is there still a huge transistor investment to go DX11?
How do you understand OpenGL3.x/4.x in that sentence you're quoting? Why mention 3.x if they'd be all 4.x compliant in the first place? A GPU that supports 4.x obviously covers 3.x too. It probably could had been worded more accurately with a "from - to" like for D3D, but apart from that I don't read anything strange out of it.