Apple will require iPhone Duo screenshots on every App Store submission from April 2027

On October 23 the first iPhone Duo buyers get their phones ^[2]. They unfold the inner display and open the apps they already had. Most of those apps will launch, according to MacRumors ^[6]. Any app not built with the iOS 27.1 SDK or later will sit in the middle of that display with black borders around it ^[7].

Inside an app team, the usual assumption is that the app works on the new phone, and on the narrow test of launching, it does ^[6]. The buyer is checking whether the app fills the screen they paid for. Apple ties its badge to the build tool. "When you build or recompile using Xcode 27.1, your App Store product page will display a badge to let people know your app is optimized for iPhone Duo," Apple wrote in its Developer News Hub post, as quoted by 9to5Mac ^[4]. Checking the fit is a separate job. For that, Apple points developers to Device Hub, a tool for seeing how an app behaves across all poses and orientations ^[9].

What Apple has made mandatory is narrower than foldable support. Starting April 2027, any app or game submitted to App Store Connect must include iPhone Duo screenshots, 9to5Mac reported ^[5]. Neither report says Apple will reject an app that does not resize, or whether App Review will accept Duo screenshots of one still sitting inside borders. The rule applies to every submission, so a team's first update after April carries Duo screenshots whether or not anyone touched the layout ^[5].

The launch window is short. Submissions opened on October 5 ^[1], 18 days before deliveries ^[11]. Xcode 27.1 reached Release Candidate 1 that same day ^[3], so any launch-week badge comes off a release-candidate toolchain. Until retail units arrive, Device Hub and Apple's in-person workshops over the coming days are the testing routes the sources describe ^[9][10]. After launch, teams get about five months before the screenshot rule starts ^[12].

I think most teams should recompile with Xcode 27.1 now and submit only after the app holds up in Device Hub in every pose. Apple says recompiling adds Duo development support ^[8], and building on the 27.1 SDK is the precondition for filling the inner display at all ^[7]. The tradeoff is timing. Waiting means launch weeks spent inside borders on the phones of people who bought the larger screen ^[7]. Rushing means a badge that promises a fit the app may not have in some pose, built on a release candidate ^[3][4].

Two axes sort a team into four boxes. The first is whether the app, after a recompile, fills the inner display correctly in Device Hub. The second is whether the team needs to be in the store for launch week or can wait for its normal release train. Fits and needs launch: submit now and take the badge. Fits and can wait: recompile on the next scheduled release and produce Duo screenshots before April. Breaks and needs launch: hold the submission, because the badge would advertise a fit the app lacks. Breaks and can wait is the box with a deadline. The first release after April 2027 must include Duo screenshots ^[5], and a team that wants them to show a full inner display needs the layout fix shipped first.