How to use Split View on iPhone Duo

Split View lets you run two apps side by side on iPhone Duo's 7.6-inch inner display, which Apple says is a first for iPhone. The Apple Post describes it as part of the iPhone Duo multitasking in iOS 27.1, which iPhone Duo shipped with, per Apple's announcement. It only works when iPhone Duo is unfolded and held sideways, according to MacRumors' Split View how-to.

Apple's iPhone Duo page says multitasking "has never been easier." The fine print: the layout is simpler than iPad's.

The split is fixed at 50/50

Each app gets exactly half of the inner display, and you can't drag the divider to give one app more room, MacRumors reports. iThinkDifferent flagged the fixed layout in September and noted that Apple hasn't explained it or said whether resizing could arrive in a later update.

MacRumors' Tim Hardwick offers a likely reason in his comparison with iPad Split View: the inner and outer displays share a 1:1.4 aspect ratio, so each half of the inner display is roughly the shape of the outer screen, with the divider on the fold. That's his analysis, not Apple's.

The divider still has two jobs. Tap it and the two apps lock into an app pair; drag it all the way to either edge and the app you push off closes, per MacRumors. Marques Brownlee says in his iPhone Duo review that a locked pair "visually looks like a book." Apfelpatient adds that pairing plays an animation with no text label.

MacDailyNews' summary of Marques Brownlee's review says he counted paired apps that launch together among the phone's strengths. More in our MKBHD iPhone Duo review summary.

Saved app pairs

Apple says you can save pairs of apps and return to them later, according to its iPhone Duo announcement. Once a pair is locked, opening either app from its icon opens the other beside it, MacRumors says.

Apfelpatient adds that pairs reappear in the same arrangement every time they launch. TapSmart says paired apps appear together in the App Switcher.

To break a pair, drag the divider all the way to an edge, MacRumors says. Sources disagree here: TapSmart says tapping the divider again also separates the apps, while MacRumors describes only the drag, which also closes one app.

Two windows, drag and drop, and Siri

Split View also works with two windows of one app. Apple's example is Safari; MacRumors lists Safari, Mail, Notes and Files as apps that can do it in some cases. To open one, tap the same app's icon again on the Home Screen or in App Library, per MacRumors.

Apple's iPhone Duo page shows a picture being dragged from Photos into Mail on the other side of the screen. Your Mac Tech says drags work for images, links and supported documents, and suggests Share or copy and paste when an app won't accept a drop.

Siri can take one side, too. Apple's October newsroom post shows Siri and Mail side by side, and MacRumors' iOS 27 explainer says you can run Siri AI on one side while viewing other content on the other. One catch: only one app can play audio at a time, MacRumors says.

What happens when you rotate or close iPhone Duo

Turn iPhone Duo upright and only one app stays on screen; the pair returns when you rotate back, according to TapSmart and Your Mac Tech.

Sources disagree on which app stays. Your Mac Tech says it's the active app; Apfelpatient says it's always the one on the right, whether you rotate or fold the phone, and suggests putting the app you'll keep using there. Apple hasn't said. Apple's product page and newsroom posts don't spell out what happens to Split View when you close the phone; Apple says only that iOS reacts as iPhone Duo folds and switches to the appropriate display when it's flipped over.

One portrait exception: Apple's iPhone Duo page says you can pin a video to the top and watch it while using another app, and TapSmart says this works in portrait.

Which apps work in Split View

Apple says its own apps are optimized, and its announcement names Netflix, Zoom and Slack among third-party apps already using the folding design. Optimized apps carry a Made for iPhone Duo badge on the App Store, per Apple's developer newsroom post.

Apps that haven't been updated still run, but in a compatibility mode at their usual iPhone size, so they can look boxed in, according to an Apple engineer on Apple's developer forums. Dexerto reports that Marques Brownlee named Spotify, Google Maps, Discord, X and Google Calendar as apps not yet properly optimized. Our productivity apps guide tracks which are ready.

How it differs from iPad Split View and Stage Manager

iPad has let you resize Split View apps in landscape since iOS 9 in 2015, MacRumors notes, while iPhone Duo keeps both apps at half each.

Apple's iPhone Duo page and newsroom posts describe two apps side by side and don't mention Slide Over, Stage Manager or more than two apps at once. That's a narrower tool than iPadOS, but not a harder one: two apps, one tap to pair, one drag to close. See also iPhone Duo vs. iPad mini.

Troubleshooting

• Nothing happens: unfold iPhone Duo and hold it in landscape, TapSmart says.
• The App Switcher opens instead: TapSmart says any pause opens the App Switcher and recommends one smooth swipe, while MacRumors and others describe a brief pause in the center before dragging to an edge. If one method fails, try the other.
• A pair vanished: dragging the divider to an edge unpairs the apps and closes one, per MacRumors.
• No second window: the app has to support multiple windows, TapSmart says.
• Black bars or a tiny app: the app likely hasn't been updated and is running in compatibility mode at its usual iPhone size, per the Apple engineer; look for the Made for iPhone Duo badge and install updates.
• No sound from one side: only one app plays audio at a time, MacRumors says.

Bottom line

Split View on iPhone Duo is useful but basic: fixed halves, saved app pairs and drag and drop, without iPad-style resizing. Apple hasn't said whether a resizable divider is coming, and we'll update this guide if iOS changes it. More shortcuts are in our iPhone Duo tips guide. Which app pairs are you using?