Apple's iPhone Duo: The $1,999 foldable ships with Touch ID and app gaps

Apple has released the iPhone Duo, its first folding smartphone, priced at $1,999. The device enters the market seven years after Samsung launched the Galaxy Fold in 2019. Apple states that the delay allowed for extensive hardware refinement, a process the company describes as having paid off in the final product.

The software experience remains the primary variable for early adopters. The phone features a 5.4-inch outer screen and a 7.6-inch inner display, a form factor that many applications do not yet support. While Apple's native apps render correctly, numerous third-party programs display as a narrow vertical strip with black bars on the sides. Slack, Instagram, DoorDash, and WhatsApp have received updates for iOS 27.1, though some, including Instagram, still exhibit broken interface elements.

The Duo marks a departure from recent iPhone security standards by dropping Face ID. Apple replaced facial recognition with a Touch ID sensor located on the right side of the device. This is the first time a flagship iPhone has used fingerprint authentication, although the technology remains on the iPhone SE, iPads, and MacBooks. The thin profile of the Duo is the likely reason for the design change. The Dynamic Island remains, but it has moved to the top-right edge above the outer camera.

Accessories require adjustment for the new shape. The phone supports MagSafe, but its uneven weight distribution causes it to tip when attached to car docks or tripods while unfolded. Third-party manufacturers may need to use anti-rotation magnets to fix this. Magnetic wallets attach to the device but extend past the bottom edge because the Duo is shorter than other iPhones. Apple has not provided an official fix for the wallet overhang.

The camera system introduces new functionality. Users can take selfies using the rear cameras while previewing the image on the outer screen. A control labeled "Slide to show camera" moves the full camera app to the outer display, disabling the inner screen to prevent accidental touches. Separate features include "Duo Preview," which shows the viewfinder to the subject, and "Kids Cue," which plays Snoopy animations to hold a child's attention.

Multitasking on the inner screen allows users to drag an app to either side to run two programs side by side. Tapping the middle bar locks the two apps as a pair, making them accessible from the Recent apps menu. However, the pair cannot be saved as a single icon on the home screen.

Apple warns users to be careful with the inner display. The screen has a matte nano-texture finish that Apple calls an "integral" component. The company's support page advises users not to attempt to remove it, noting that doing so could void the warranty. Apple does not address third-party screen protectors, which may affect display performance. A damaged finish costs $19 to replace in warranty or $49 out of warranty. A cracked inner display costs $999 without AppleCare+.

Additional software features are scheduled for later this year. A future update will add Reachability, which shifts apps to the side rather than down, and support for the USB-C Apple Pencil. The pencil is designed to work with the nano-texture screen for writing and drawing. There is no physical slot to store the stylus on the phone itself.

The keyboard can currently be split to facilitate typing on the wide inner display. The device is back-ordered for several weeks, meaning many buyers may receive the phone after developers have optimized their applications for the new screen layout.