The iPhone Duo now has more than 100,000 optimized apps: what that means and how to check yours

Two weeks after it hit stores, the iPhone Duo is starting to answer one of the most common criticisms in the early reviews: apps that don’t take advantage of the inner display. Apple says the App Store already has more than 100,000 apps built for the iPhone Duo, with thousands more added every day. Here’s what that number means, which apps are already adapted, which still aren’t, and how to check.

What Apple has confirmed

The figure comes from a statement by Susan Prescott, Apple’s vice president of Developer Relations, sent to the press on November 6. These are the official points:

• More than 100,000 apps built for the iPhone Duo are already available on the App Store, and thousands of optimized apps are added every day.
• Over the past month, Apple has held more than 50 in-person workshops in 19 cities, attended by more than 2,000 developers who came to try the Duo and adapt their apps.
• The App Store shows a “Made for iPhone Duo” badge on the page of optimized apps (you see it when you browse from the Duo itself) and keeps collections like “Popular Apps on iPhone Duo” and “Great Games on iPhone Duo.”
• Among the latest apps to be adapted are Microsoft’s Word, Excel, PowerPoint, OneNote, and Outlook, plus Zoom, Etsy, Goodnotes, and Halide Mark III. Word and Outlook weren’t ready on launch day.

What counts as “optimized”

Every App Store app runs on the iPhone Duo, but they don’t all look the same on the inner display. It all depends on the SDK (Apple’s developer tools) the app was built with:

• iOS 26 or earlier: the app works, but it appears centered, with a lot of black space on the sides.
• iOS 27: it fills almost the entire inner display, but leaves the status bar area on the right edge empty.
• iOS 27.1 or later: it uses the full width of both displays and places its controls vertically next to the status bar. These are the ones Apple considers optimized.

That’s the key detail: Apple has confirmed that the 100,000 apps are the ones built with the iOS 27.1 SDK or later. Remember that the Duo has two displays with the same aspect ratio, a 5.4-inch outer one and a 7.6-inch foldable inner one, so an optimized app adapts to both and to switching between them.

Which apps are ready and which are missing

Many of the most popular apps in the US are already optimized: WhatsApp, Instagram, YouTube, Netflix, and Prime Video, plus the Microsoft apps I mentioned. In October, Apple also highlighted apps from independent developers like Tripsy (travel), SmartGym (workouts), and Moises (music).

On the other side, as of November 6, everyday apps like Google Docs, Sheets, and Slides, Microsoft Teams, Duolingo, PayPal, YouTube Music, Uber Eats, Starbucks, Steam, and Bluesky still weren’t optimized. Not even Apple’s own Apple Store app had been adapted.

How to check whether your apps are ready

1. On the iPhone Duo, open the app’s page in the App Store and look for the “Made for iPhone Duo” badge.
2. If it doesn’t have it, check for pending updates. Thousands arrive every day, and several apps that were adapted on launch day have already received a second update that improves how they use both displays.
3. If you don’t have the Duo yet, make a list of the five or six apps you use most (banking, transit, work) and check them in the store or on the developer’s website before you buy.

My take

100,000 apps in two weeks is a good pace, but it needs context: the App Store has millions of apps, so the vast majority still aren’t adapted. And building an app with the new SDK isn’t the same as redesigning it for a foldable. Filling the whole screen is the bare minimum; the interesting ones are the apps that truly take advantage of the format, like Zoom or Word in split view.

There’s one more nuance: big national and international apps tend to adapt first, while smaller banks, regional transit apps, or local services can take longer. With a starting price of $1,999 in the US, it’s worth checking first whether your everyday apps already carry the badge. And if you already have one, Apple is also asking buyers what they think: I covered it in the survey about the crease and the camera.

Which app do you miss on the iPhone Duo? Tell me in the comments or on social media.

Sources: 9to5Mac (Apple statement), MacRumors (optimized and pending apps), Apple Newsroom (apps for the iPhone Duo). Data as of November 6, 2026.