DuoAppsiPhone Duo case studies: what Apple shows
What Apple shows of iPhone Duo in its public pages and videos, app by app and question by question, described without a verdict: what you see, what Apple says about it, with sources, and what the source doesn’t say. When a question goes beyond what Apple shows, our hypotheses are labeled as such.
By question
Vertical controls on iPhone Duo: when apps use them, and when they don’t
By default, they’re there: the system puts the toolbar, the tab bar, and navigation buttons on the side, except on the inner display in portrait. Apple also shows where they don’t go: an immersive interface that doesn’t scroll (Calculator), a sheet with a single button, a text item, and the columns of a split view (list and detail) other than the detail. On the inner display, an information-dense app can present its tab bar as a sidebar (Health).
Full screen or a list alongside: how to choose on iPhone Duo
Apple gives one criterion: the relationship between the two views. When one serves as the background for the other, like a video under its playback controls, the content takes the whole screen and the controls sit on top of it (overlay); partially folded, the two views move side by side. When one details the other, like a podcast’s transcript or a player’s “up next” list, they stay side by side (split) and neither is ever hidden. The newsroom photos show both: Netflix full screen, Slack with its list alongside.
By app
Mail on iPhone Duo: what Apple shows
Apple shows Mail on both displays of iPhone Duo. With the device closed, on the outer display, Mail shows either the list of emails or a single email. With the device open, on the inner display, it shows both side by side: the controls for the list stay above the list, and those for the email move to the side, along the edge of the screen.
Notes on iPhone Duo: what Apple shows
Apple shows Notes on the inner display of iPhone Duo, in a split view: the list of notes on one side, the open note on the other. Fully open, the list is narrower than the note; partially folded, the split view gives both columns the same width on its own. Apple also names New Note among the actions to keep visible the longest.
Calculator on iPhone Duo: what Apple shows
Apple shows Calculator on the outer display of iPhone Duo: the app takes the full width of the screen, with a keypad of five columns of four keys, compared with four columns of five on iPhone 16. Apple cites Calculator as an example of an app that can do without controls on the side (vertical controls): a single page, visual, that doesn’t scroll, with a bottom-heavy layout.
Netflix on iPhone Duo: what Apple shows
In the photo Apple published, Netflix fills the inner display of iPhone Duo, in landscape: the image of a show fills the whole screen and runs under the controls. The controls sit on the right edge, in two groups: three buttons at the top, the tab bar at the bottom. No sidebar. Apple says what Netflix is going for, not why the app is built this way.
Slack on iPhone Duo: what Apple shows
In the photo Apple published, Slack fills the inner display of iPhone Duo, in landscape, in two columns: on the left, the list of conversations, with its buttons at the top; on the right, the open conversation, with its controls on the side and the tab bar at the bottom. In a message, a row of photos runs under those controls; the text and the input field stop short of them.