iPhone Duo's next-gen prototypes are trying to cram in Face ID

Apple's first foldable phone opted for a feature it replaced on most iPhone models nearly 10 years ago.

Apple's first foldable phone opted for a feature it replaced on most iPhone models nearly 10 years ago.<p><img src="https://www.engadget.com/img/gallery/follow-up-iphone-duo-prototypes-trial-faceid-instead-of-touchid/intro-1792677641.jpg" /></p>