I know a lot of these rumors end up not being true, but a lot of evidence points to this year's upcoming iPhone having largely the same design as this year's. As a result, here's my small prediction: the next iPhone will not be called iPhone 7, but rather iPhone 6SE and iPhone 6SE+. The 2017 model with the thinner bezel and Touch ID incorporated into the screen will be the iPhone 7.
No way they will have a "special edition" iPhone 6 released the year after the 6 series. They will most likely call it the 7, and then the 7S may have a special name because it'll be the 10th anniversary of iPhone. Keeping the iPhone 7 simple, with only minor physical changes will give Apple the chance to make a really bad ass, OLED, edge to edge, bezeless, curved sapphire phone next year for the 10 year mark. If this is the plan I am all for it. But they better bring that wow factor in 17. Because investors and customers a like will not be very happy this year.