The iPhone might radically change in 2017
Gruber is very plugged into the Apple community, and he often has good intel on what the company is working on.
According to Gruber, who cites rumors he's personally heard, "the entire face [of the iPhone] will be the display." That suggests there will be no bezel or borders like there has been on every iPhone model so far.
He goes on to suggest that the sensors, front-facing camera, and speaker will all be embedded into the display.
Gruber's mention of embedded sensors lines up with previous rumors that Apple may be embedding the home button and Touch ID fingerprint sensor into the display. There's some discrepancy, however, as those rumors refer specifically to the iPhone 7, which is expected to launch in the fall of this year.
If it's a total redesign, it's not clear what the 2017 iPhone will be called. Apple typically releases an "S" model of the iPhone every other year, and 2017 would be when the "iPhone 7s" is due. However, a Barclay's analyst has speculated that Apple will ditch the "S" generation strategy. That means we could see the iPhone 7 in 2016 and the iPhone 8 in 2017.
2017 will mark the iPhone's tenth anniversary, so it wouldn't be surprising if Apple had something special planned to celebrate the tenth year of the device that helped the company become the most valuable in the world.