According to this page on Samsung's Developer Site:
You will need the following hardware to develop for Gear VR in Unity:
Samsung Gear VR Innovator Edition for Note 4 and Samsung GALAXY Note 4
Samsung Gear VR Innovator Edition for S6 and Samsung GALAXY S6 or S6 Edge
Is the Innovator Edition required for development?
Or can I use the new Samsung Gear VR for development of VR apps, games and experiences?
It seems as if this page simply hasn't been updated, because the S6 is mentioned when the s7 is already available, but I want to be sure before getting started.
Yes for sure you can all you need to have
Hardware :
Samsung gear vr
A compatible Samsung phone (S7 or Note 8 for example)
Software :
Android studio
JDK 1.7 or above
Oculus Mobile SDK
Google VR SDK
create an account in https://dashboard.oculus.com/tools/osig-generator/ and follow steps to get signature files
finally follow the steps in getting started (download simple project on modify files like it's mentioned) http://www.gearvrf.org/getting_started/