The little circle at the bottom of the phone has been the main way of identifying Apple's handsets, at least when they're turned off. But it's about to disappear in the iPhone 8.

That's according to code that was accidentally released by Apple. Part of that includes a check on whether a device has a home button – something that was previously unrequired, since every iPhone had one.

It's possible that the reference is to other devices that run some form of iOS and don't have a home button, like the Apple TV. But the removal of the home button in the iPhone squares with other code found in the release, pictures that are also included within it, and years of rumours.

Pictures found in the code that appear to depict the new phone, for instance, show the design including some of the "forehead" that sits at the top, but none of the "chin" at the bottom that houses the button. As such, there appears to be no space for a physical home button and it will presumably be depicted on screen instead, as it is on Android.

Some had hoped that the long-rumoured removal of the home button would actually mean that it was hidden under the bottom of the screen, and that the fingerprint sensor would shine through the display. But there appears to be no such reference to a TouchID fingerprint sensor, and so it's likely that the button will be entirely virtual.

That will also mean that the button can move out of the way when it is not required, such as when people are watching videos.

Code found by developers including Steve Troughton-Smith and Guilherme Rambo suggest a major re-design to the phone. They and others have been picking through firmware that was apparently accidentally made available online, and includes references to many unreleased features.

They have also found suggestions that the phone will be able to track people's faces. That will apparently be used to unlock the phone, as well as to see whether people are paying attention to the screen and so change things on the display accordingly.

The firmware was actually made for Apple's upcoming HomePod smart speaker, but it included numerous references to the new phone and other hardware as well.