iPhone Duo: concise rundown of every small detail Apple revealed

iPhone Duo is Apple's first foldable iPhone and the company positions it as a new form factor with two displays, strong cameras, and long battery life. Beyond those headline points, Apple revealed a number of smaller, concrete design and software choices that affect daily use. This brief gathers those specifics so you can evaluate trade-offs before ordering.

The Duo uses a folding display with an under‑display camera on the inner screen, which gives a cutout‑free inner viewing area. Apple notes the under‑display camera is less capable than the outer display's Center Stage front camera, so using the outer camera is preferable for higher‑quality selfies and video calls.

Duo does not include the variable aperture found on the iPhone 18 Pro. Apple also lists several camera‑focused software exclusives for Duo: Smart Take, Kid Cue, and Duo Preview.

Apple replaced the Action button found on recent iPhones with a Camera Control button on Duo. If you prefer the Action button's functions on other models, that choice will be absent here.

Because iPhone Duo ships later than other new iPhone models, it will run iOS 27.1 out of the box. Apple lists several Duo‑specific camera software features (Smart Take, Kid Cue, Duo Preview). Separate reporting and leaks also point to additional StandBy‑mode features discovered in iOS code, indicating Apple may expand Duo's software functionality closer to or after shipping.

iPhone Duo is eSIM‑only across all markets. Apple explicitly states no physical SIM option will be offered anywhere in the world, including China where physical SIM use remains common.

Release timing is concrete: orders begin October 16 and units ship to customers the week after, on October 23.

Small details that affect daily use

• Use the outer display for selfies when possible because the under‑display inner camera performs worse.
• If you value the Action button for quick shortcuts, Duo replaces it with a Camera Control button.
• If you plan to use Apple Pencil with Duo at launch, confirm you have or will buy the USB‑C Pencil rather than the Apple Pencil Pro.
• Duo arrives with iOS 27.1, so expect software features and potential additions tied to that update.
• The absence of a physical SIM requires checking carrier eSIM support and any phone‑number porting nuances in your market.