How big is the chance that the Antminer S2 upgrade set will be using the same (newer) asic chips as the Antminer S6.
I truly believe there's a great chance.
I would be to expensive to create faster hashing chips in such a small timeline between S2 Upgrade an S6.
Using the same chips for S2 Upgrade and S6 gives them some extra space developing 16nm for future.
From what I've heard from the people receiving batch 5 of the S5, some are receiving clearly used miners, so the educated assumption would be that bitmain are not simply testing the next-gen chip to feature in the S6, they are actually replacing their S5 rigs with the newer S6 in their facilities. What has that got to do with the S2 upgrade kits I hear you ask? Well, I bet top dollar that they will have the chips in the S6, seeing they could have released an S5 chip based kit by now.