I'm pretty sure that the iPhone 6s/7 control layout is basically the same as the one on the iPhone 5, just scaled up, which fixes the zoom out issue, but ends up making the d-pad and other elements much larger than they're supposed to be,
d-pad on the iPhone 6s/7 (photo creds to Vic):

d-pas on the iPhone 6:

this is preventing me from playing Graal on any of the new iPhone models, can this issue be addressed @devs? I'm offering to ship my iPhone 6 to any dev that will use it to address related issues