> iPhone Duo App Store Screenshot Sizes and Deadline

Apple opened App Store submissions for iPhone Duo optimized apps in early October, a few weeks ahead of the October 23 launch. Along with that, App Store Connect's screenshot specifications picked up the new device, so the sizes that were listed as "later this year" back in September are now live and uploadable.

There's also a deadline attached, and it's closer than you might expect. More on that below.

The Sizes

iPhone Duo is the first iPhone with two screenshot sets, one per display. The outer display takes 1398 x 2034 pixels in portrait or 2034 x 1398 in landscape. The inner display takes 2007 x 2853 in portrait or 2853 x 2007 in landscape.

Both displays render at 3x, so those work out to 466 x 678 points for the outer display and 669 x 951 points for the inner one. If a screenshot comes out at some other size, something upstream resized it and App Store Connect will reject the upload.

The usual rules apply beyond that. You can upload up to ten screenshots per device size, in JPEG or PNG, with no alpha channel or transparency. Note that the outer display is a noticeably wider aspect ratio than any other iPhone, so there's no existing set you can crop or letterbox into shape without it looking wrong.

Capturing Them in the Simulator

The simulator is the easiest place to get pixel-perfect captures, and for iPhone Duo that specifically means Xcode 27.1. Xcode 27 has no Duo device type, and somewhat confusingly, neither does the current Xcode 27.2 beta. I covered that mess in Xcode 27.1 beta or Xcode 27.2 beta.

With the Duo simulator booted, use Device Hub to put the device in the pose you want. Closed gives you the outer display, fully open gives you the inner display, and rotating in each pose gets you the landscape variants. Cmd+S in Simulator saves the live display at native resolution. From a script, simctl can capture either display regardless of pose:

xcrun simctl io booted screenshot --display=primary outer.png
xcrun simctl io booted screenshot --display=primary-1 inner.png

The displays are named primary (outer) and primary-1 (inner). Don't reach for --display=external, which hangs for a minute before failing.

One thing worth keeping in mind while you're at it: App Review guideline 2.3.3 says screenshots should show the app in use on that device. Capture each display from an actual run of your app, after your Duo layout work is in place. Scaling up an existing iPhone render, or exporting a landscape frame from a portrait capture, is the kind of thing that gets a metadata rejection. If your inner display still shows a stretched phone layout, fix that first. My iPhone Duo preparation checklist walks through what to look for.

App Store Connect also gained a preview tool that shows how your screenshots and product page header will look on the device itself, which is worth a pass before you submit, since the vertical bar on the outer display crops product pages differently than you'd guess.

When They Become Required

Right now, iPhone Duo screenshots are optional. The only mandatory set is still the iPhone with Dynamic Island one, and listings without Duo screenshots simply keep showing what they show today.

That changes in April 2027. Apple's announcement puts it plainly: "Starting April 2027, any apps or games submitted will need to include screenshots for iPhone Duo." The screenshot specifications page scopes it slightly more precisely, saying screenshots will be required for any app using the iOS 27.1 SDK or later. The distinction barely matters in practice, because April 2027 is also when Apple's annual SDK floor moves up and uploads must be built with the iOS 27 SDK or later. You won't be able to sit on an older SDK to avoid it.

So the honest framing is this. New app or update, if you submit anything after April 2027, budget for four more screenshots at minimum, one per display, and realistically a localized set if you localize the rest of your listing. Nothing about the deadline forces you to add Duo-specific features. A compatibility-mode app still needs the screenshots, and they still need to show the app as it actually runs, stretched layout and all. Which is a decent argument for doing the layout work before you're contractually showing it off on your product page.

If you're already in the simulator doing Duo work for launch, grab the captures now while everything is set up. Future you, staring down an unrelated bug fix release in May 2027, will be glad the folder is already full.