While it seems pretty certain that the next iPhone will come with a fingerprint scanner, what it will look like remains an open question. A "silver ring" around the home button (see below) is the prevailing theory; our friend Martin Hajek has taken a closer look at what that might mean in practice.
Sure, these are just renders. But they're an excellent hint at what the Eye of
Sauron Siri will look like in practice. And it's likely to be just about the only difference you'll notice between the iPhone 5S and the one that came before it.