Apple is reportedly already testing iPhone Duo 2 prototypes that include Face ID, with the sensor integrated beneath the display on the outer screen. Mark Gurman made the claim on his Power On podcast, noting that the shift from Face ID to Touch ID on the first iPhone Duo was one of the biggest complaints from early reviewers. 9to5Mac's Chance Miller called it "the hardest thing to get used to" with the new foldable.
Fitting Face ID inside the super-thin enclosure appears to have been the blocker for the first-generation model. Apple has been working on making Face ID smaller and less obtrusive, as seen with the under-display IR camera on the iPhone 18 Pro. With the iPhone Duo 2 and the twentieth anniversary iPhone Pro, the IR camera and flood illuminator could both move behind the screen, allowing the bezel or Dynamic Island cutout to shrink even further.
Gurman cautioned that testing prototypes does not guarantee the feature will ship in next year's revision. Customers could see it next year or as part of the iPhone Duo 3 if development slips. On the same episode, Gurman said employees have been exploring ways to bring the Action button to a next-generation iPhone Duo, though he sounded less confident about this.
It remains unclear whether Apple would remove the Touch ID sensor from the power button if it adds Face ID, or whether it would keep both biometric methods. Either way, users could authenticate whether they are looking at the inner or outer display.
Source: 9to5Mac · Summarized by HeadlinesBriefing