I was just given the 2015 Gear VR as a gift for my Galaxy S6, but plan to upgrade to an S8 soon. I'd like to know if the S8 will be able to fit into and interface with the 2015 headset.
I see you asked this 6 months ago, but since I just got off the phone with Samsung, I thought I would answer this. Nope, the 2015 version of the Gear VR will not work with the new S8 models. Meanwhile, the 2016 version of the Gear VR will, assuming you have the USB C connector module for the Gear VR, which can be bought for $13 if you don't. (Supposedly, both the micro-USB and USB C connectors came with the 2016 version.)