Detecting the iPhone Duo

There is no API to detect whether your app is running on iPhone Duo. Is there anything in particular you are looking for?

An iPhone Duo app is still an iPhone app, and other than avoiding placing interactive UI on reserved regions, the recommendation would be to not introduce behavior that is specific to the device.

One thing to keep in mind is that all iPhone apps can be resized to any size. Starting with iOS 27, iPhone apps can be resized on iPad and on Mac via iPhone Mirroring.

If you still are looking to introduce device-specific behavior, could you please elaborate on what you are trying to build?

Here’s a case: I have a custom navigation controller implementation that I’ve been using for several years to make a navigation stack turn multi-column (like Finder) on regular horizontal size class. What do you advise in this scenario beyond “move to standard controls”?

Yes, as radutzan noted, my question is motivated by our app using custom controls and view controllers.

One example is moving a custom navigation bar into the side area, similar to how the system navigation controller adapts on iPhone Duo.

Can't you work around by detecting screen size ?

Unfortunately, I fear solutions proposed here do not work after iPhone 15.

https://stackoverflow.com/questions/26028918/how-to-determine-the-current-iphone-device-model

And I do see the duo in this list: https://gist.github.com/adamawolf/3048717