Apple today announced that more than 100,000 apps have been optimized for the iPhone Duo, released two weeks ago. We confirmed that this figure refers to apps built with the iOS 27.1 SDK or later, meaning these apps fill the full width of the iPhone Duo's inner and outer displays and have vertical controls in the status bar.
A statement from Susan Prescott, Apple's Vice President of Worldwide Developer Relations:
It's been wonderful to see how quickly developers have embraced iPhone Duo, and we're grateful for their creativity and innovation. Today there are well over 100,000 apps built for iPhone Duo already live on the App Store, and thousands of optimized apps are being added to the store each day. In the last month alone, thousands of developers have joined us for workshops in 19 cities around the world to experience iPhone Duo firsthand and bring updated apps to their users. The enthusiasm has been incredible, and we're excited to see the pace of updates continue to accelerate as more and more apps optimize for iPhone Duo.
Apple said thousands of apps optimized for the iPhone Duo are being added to the App Store each day, with recent examples including Microsoft's Excel, OneNote, PowerPoint, and Word apps, along with the Etsy, Goodnotes, Halide Mark III, NBA, NHL, and Zoom apps. Other apps optimized for the device include Amazon Prime Video, Fantastical, Flighty, Instagram, MLB, Netflix, SmartGym, WhatsApp, YouTube, and more. There are too many to list.
Apps optimized for the iPhone Duo have a "Made for iPhone Duo" badge in their App Store listings on the device, making them easy to identify.
iOS 27.2 added Apple Pencil (USB-C) support to the iPhone Duo, enabling users to draw in apps like Procreate Pocket, take notes in Apple Notes, Fineliner, and TypeDraw, and mark up documents in apps like Preview on the device.
On the other hand, with millions of apps available in the App Store, there are unsurprisingly many apps that are still not optimized for the iPhone Duo, with the following examples listed in alphabetical order: AMC Theaters, Amazon Fire TV, Apple Store, Best Buy, Bluesky, Delta, DoorDash, Duolingo, Fandango, FedEx, Goodreads, Google Docs, Google Home, Google Sheets, Google Slides, GrubHub, JetBlue, Libby, Microsoft Authenticator, Microsoft Teams, MTA, Nike, PayPal, PictureThis, Ring, Southwest, Spectrum TV, Starbucks, Steam, Uber Eats, UPS, USPS, Venmo, Verizon, Wells Fargo, Whole Foods, and YouTube Music.
Apple said developers can easily optimize their apps for the iPhone Duo. Apps that use standard SwiftUI and UIKit components adapt automatically to each display, with controls moved to the status bar and multi-column support on the inner display. New APIs let developers optimize their apps for the device's various layouts and poses.
Apple has hosted more than 50 in-person iPhone Duo app workshops in 19 cities worldwide, and there are online resources like the Apple Developer Forums.
In the meantime, apps built with the iOS 27 SDK resize to fill most of the inner display on the iPhone Duo, but they avoid the status bar on the right edge. Apps built with the iOS 26 SDK or earlier run on the iPhone Duo, but appear in the center of the inner display, with lots of empty black space on the left and right sides of the apps.
iPhone Duo app optimization has been a hotly debated topic on social media platforms, with some people pointing out apps that are not yet optimized and others saying the issue is overblown. It is clearly a mixed bag, with some apps optimized and some not. More apps are being updated by the day, though, so the situation is improving rapidly.
