Foldable iPhone Duo: Apple Will Label Compatible Apps in the App Store

Apple's foldable phone, the iPhone Duo, goes on sale this Friday. The App Store will mark apps optimized for the device with a "Made for iPhone Duo" label. The real problem with foldables isn't the hinge. It's apps that don't fit the big screen. Apple is trying to fix that from day one, using its storefront.

What happened?

Apple announced that compatible apps will be labeled in the App Store. To get the label, developers have to build their apps with the iOS 27.1 SDK or later. These apps use the entire inner display, and their toolbars sit vertically below the status bar. Apps built with the iOS 27 SDK fill most of the inner display but stay out of the status bar area along the right edge. Apps built with the iOS 26 SDK or earlier still open, but they run in a centered window with empty space on both sides.

Why does it matter?

Apple has seen this movie before. When the iPad launched in 2010, many iPhone apps ran on the big screen either scaled up or in a centered box. Compatibility mode saved the device's launch, but it also let some developers get lazy. Several major apps took years to ship a native iPad version, and Instagram is the best-known example. That's a big reason it took the iPad so long to stop being seen as a "big iPhone."

Android offers an even more telling lesson. Samsung has been selling foldable phones since 2019, yet many apps still look stretched on the inner display or open with black bars along the edges. Google published app quality guidelines for large screens and started highlighting large-screen support in the Play Store. Those steps came years after the hardware hit the market, though. Apple's edge is timing: its guidance starts the same week as the device.

The tiered SDK setup also looks deliberate. Older apps open without breaking, so users don't run into "this app doesn't work" on day one. But the empty space on either side of the screen is a reminder, every time the app opens, that it hasn't been updated. Users will notice the difference, and their complaints will go to the developer.

What changes for developers and users?

The three compatibility tiers can be summed up like this:

For developers, the label is an optional badge on paper. In practice, it will probably become a requirement. If labeled apps get more visibility in App Store search and featured lists, competitors without the label will fall behind. Apple also raises the minimum SDK version for App Store updates every year. That schedule will move everyone to the new SDK sooner or later. The label is an incentive to make the switch sooner.

The real work goes beyond recompiling. Full-screen layouts and vertical toolbars mean the interface has to adapt to a new aspect ratio. Modern apps built with SwiftUI and Auto Layout can make the switch fairly easily. Banking, government and enterprise apps running on older codebases may lag behind. That's the key issue for users in Türkiye: the local banking, e-Devlet-style and shipping apps they use every day will most likely be the last to become compatible.

For users, the label works as a buying guide. Someone spending a lot on a foldable will be able to see at a glance in the store whether their most-used apps are ready. On Android foldables, people still find this out by trial and error.

What's next?

The first signal to watch is how quickly the major platforms move. If messaging, social media and video apps earn the label in the first few weeks, the device's reputation will settle quickly. If they don't, the "scaled-up iPhone" criticism from the iPad's early years could come back.

The second question is how prominent Apple will make the label. Will it be a small note on the product page, or will it work as a filter in search results? That choice will directly shape how developers set their priorities. The third is when Apple will raise its minimum SDK requirement. Developers can follow current requirements on Apple Developer.

The bottom line: Apple came late to the foldable market, but it seems to be using that delay to get the app ecosystem in order ahead of time. A label alone won't guarantee compatibility. Still, using store visibility as leverage over developers may be the most direct answer yet to a problem Android hasn't solved in years.