Which apps are optimized for iPhone Duo?

Why almost every row is empty

The first toolchain that can build for iPhone Duo arrived on 18 September 2026. Apple’s developer news said on 16 September that Xcode 27.1 would add development support for iPhone Duo, with updated SDKs and a simulator for the new poses, and that a beta would follow later that month. The device ships on 23 October.

That leaves about five weeks between the first Duo simulator and the first customer. A developer who has not announced anything four weeks out is on schedule, not asleep. Read an empty row as a date, not as a verdict.

The App Store record says the same thing more plainly. Of the 37 apps checked there, not one mentions iPhone Duo, Split View or a foldable display in its release notes. Thirty-two of them shipped an update after the 9 September announcement and still said nothing. The other five last shipped before it, so their silence carries no information at all, and the table says which is which.

What Apple has published, and what it has not

Apple’s announcement names Netflix, Zoom and Slack in one sentence, and Detail in another. Those four are the complete set of third-party apps Apple has named anywhere. Each is described doing one thing, in a caption written by Apple for a demo.

There is no Apple compatibility list. Apple’s support site has no iPhone Duo page, and the iPhone User Guide contained no iPhone Duo content when it was checked on Sep 20, 2026. Whether the App Store ships a Duo collection on launch day is not something anyone outside Apple can answer yet.

Check an app yourself, in about a minute

1. Open the app’s App Store page and read the latest release notes, not the description. The description is marketing copy that can sit unchanged for years; release notes carry a version and a date.
2. Search that text for iPhone Duo, Split View or foldable. A real adaptation is usually mentioned, because developers want the credit.
3. Check the developer’s own channels: a blog, a changelog, a help centre, the company account on a social network. A statement of intent lives there long before a release note does.
4. Write down the version number and the date you checked. An answer without those two is not reusable a week later.
5. Treat silence as silence. An app with no announcement still runs on iPhone Duo; how much of the inner display it uses is set by the SDK it was built with, which its release notes do not tell you.

What a row does not tell you

This table records publishing, not behaviour. A developer statement is a promise with a date on it, and an app named by Apple was shown doing one specific thing. Neither is a report on the version you will download. Adaptation status also changes with every release, so each row is a snapshot carrying the date it was checked rather than a standing answer.

For what the three levels of screen usage actually mean, read the app compatibility guide. For the apps we have enough to write about properly, open the directory.