Apple's next iPhone will be unlocked using facial-recognition technology and will feature a screen covering almost its entire front, according to reports.

A pre-release of firmware for the tech giant's upcoming HomePod smart speaker, due to launch late 2017, contained hidden details about several new features for the world's most popular smartphone.

Sent out to developers last week, the firmware – permanent software programmed into a read-only memory – was found to contain references to other products, including one codenamed D22.

Developers have claimed this will be the next iPhone iteration, which is expected to be announced in September 2017, and launched shortly after.

The firmware outlined the use of infrared facial recognition, which could be used to unlock the phone rather than a passcode or a thumb scan. Both Microsoft and Samsung have already introduced similar features into computers and larger smart devices.

The developers, Steve Troughton-Smith and Guilherme Rambo, said that Apple has codenamed the tech Pearl ID and referred to it throughout the HomePod firmware.

The pair also found a visual icon used to represent D22. It looks like a smartphone, with no home button and a screen that wraps the full front, apart from a small portion at the top reserved for a camera, speaker and sensors. Rambo shared the image on Twitter.

The new iPhone will work on the upcoming version of Apple's operating system, iOS 11, which the company has already confirmed will automatically block incoming notifications while driving.

Speculation around the device's name includes iPhone 8 – following consecutively from the previous iPhone 7 – and iPhone X or iPhone 10, as the first version of the smartphone was released a decade ago.

Apple – which was beaten by IKEA in the Brands category of the first Dezeen Hot List – is currently moving into its vast new headquarters in California. The company's head of design Jonathan Ive recently revealed his feelings about the building in an interview with WSJ Magazine.