I thought the main difference between HBM 1 and 2 what the memory limit not the speed. It does have double the throughput though 128 bit vs 256 so I guess it is faster because of the throughput. But, I just don't know enough about it to say for sure. I would love to know what the speed differences are.
Any ways getting back to your question see the article below. It is coming just have to wait. We will probably see it in the new Titan (?) which will probably use more memory than the upper limit of HBM 1.0 and will require the HBM 2.0.
http://videocardz.com/55259/sk-hynix-shows-off-hbm1-and-hbm2