Last updated: October 24, 2026. This is a living guide — we'll keep updating it as Apple shares more and we ship new RevenueCat Paywalls features for foldables. So bookmark this and check back.

TL;DR

Build with Xcode 27.1, present your paywall in a sheet, and turn on Use system navigation for your close button (it needs purchases-ios 5.98.0 or later). iOS then puts Close in the vertical side bar on iPhone Duo, right where people expect it. You can submit iPhone Duo-optimized apps today, and starting April 2027 every app you submit will need iPhone Duo screenshots. For more, see “Check your close button” and “Ship it” below.

iPhone Duo gives your app two very different screens to lay out for, plus everything in between. And your paywall is the one screen where something looking ‘a little off’ costs you real money.

A paywall is already one of the hardest screens to get right on a normal iPhone. Now the same paywall has to work on a 5.4-inch outer screen, a 7.6-inch inner screen, sideways, half-folded on a table, and in Split View next to another app. If you present your PaywallView in a .sheet like most of us do today, it'll show up in every one of those states, so we want to make sure that everything still looks intentional.

This guide covers what iPhone Duo is, and what each posture does to your paywall. Plus, what Apple recommends, and exactly how to set up a RevenueCat paywall so it feels native on Duo starting today.

What is iPhone Duo?

iPhone Duo marketing image

iPhone Duo is Apple's first foldable iPhone. It has a shape like a passport and opens like a book to about the size of an iPad Mini.

iPhone Duo went on sale Friday October 23, 2026, running iOS 27.1. You can test it today with the iPhone Duo simulator in Xcode 27.1, and you can already submit iPhone Duo-optimized apps to the App Store.

The simplest way to think about it: closed, it's an iPhone; open, it's much closer to an iPad. Apple's Human Interface Guidelines (HIG) ask you to design for two sizes: compact width on the outside and regular width on the inside.

Lots of different postures

This is where things start to get really interesting...

iPhone Duo can be closed, fully open, or angled somewhere in between. Apple's hinge API (onHingeChange in SwiftUI, UIHingeInteraction in UIKit) reports these as .closed, .partiallyOpen, or .fullyOpen. On top of that come portrait, landscape, and a few ways to set the phone down.

Different postures of iPhone Duo
Different postures of iPhone Duo

Check your close button

RevenueCat Paywalls can now swap your close button for the system Close control. iOS puts it in the vertical side bar on iPhone Duo and in the navigation bar on iPhone and iPad. Select your close button in the paywall editor and turn on Use system navigation on the Paywall Editor. It needs purchases-ios 5.98.0 or later.

Use the Use System Navigation checkmark in the Paywall Editor (on by default for Close Paywall action).

Existing buttons keep their designed look until you turn it on. It works the same way for Back buttons in multi-step paywalls. Android, web, and hybrid SDKs show your designed button.

Using presentPaywallIfNeeded? The SDK provides the navigation bar for you, so once Use system navigation is on, there's nothing else to do.

Presenting PaywallView yourself in a sheet? The SDK adds Close to your existing navigation bar. If there isn't one, wrap PaywallView in a NavigationStack:

.sheet(isPresented: $showPaywall) {
  NavigationStack {
    PaywallView()
  }
}

Using PaywallViewController in UIKit? The SDK adds its controls to the presenting navigation controller.

Keeping your designed X? If you're on an older SDK or a hybrid SDK, or you leave Use system navigation off, your X stays inside the paywall. You can opt the sheet out of the vertical bar instead:

.sheet(isPresented: $showPaywall) {
  if #available(iOS 27.1, *) {
    PaywallView()
      .toolbarVerticalBehavior(.disabled)
  } else {
    PaywallView()
  }
}

Built a custom X into your design? Any close button you've positioned yourself, like an overlay in your own code, stays exactly where you put it. On the outer display, that can put it right next to the camera or the side bar. Check it in the Duo preview in the paywall editor and in the simulator, and move it if it collides.

One thing to know

If you do opt out, remember that the vertical bar is Apple's default. Apple says opting out "works well for sheets with only a single toolbar button," and asks you to treat it as a stable choice rather than toggling it on and off.

Then build with Xcode 27.1, check the result in the Duo simulator, and use the Duo preview in the paywall editor to tune your layout for the shorter outer screen and the wider inner one.

Official Apple recommendations for paywalls on iPhone Duo

Apple published a new HIG page for iPhone Duo and a set of tech talks alongside it. None of it is written specifically for paywalls or StoreKit, but a handful of the general rules map directly onto how a paywall should behave.

Prioritize small adjustments over big rearrangements

Apple asks you to "avoid extreme layout changes as people fold the device" and to "maintain the same functionality across device poses". For a paywall, that means the same packages, prices, trial terms, and call to action whether the phone is open or closed.

Put Close where people now expect it

On Duo, toolbars move to a vertical strip on the side. Apple says to reserve the top of that vertical axis for navigation controls like Back or Close. Turn on Use system navigation for your paywall's close button, and RevenueCat swaps it for the system control so it moves with the toolbar. The "Check your close button" section above covers the fix.

Keep anything tappable off the fold

When the device is partially folded, iOS slides sheets out of the fold for you, so a paywall presented in a sheet is covered. If you present your paywall full screen, the fold runs right through the middle of it. In that case, Apple suggests an even number of columns so nothing straddles the fold — so two package cards side by side work better than three.

Know where your sheet will land

On the inner display, sheets are centered by default. You can move one to the leading or trailing edge with presentationPlacement(_:). On the outer display, a sheet with a single button can opt out of the vertical bar and stop just short of the camera.

Adapting your existing paywall for iPhone Duo

You don't need to wait for anything new to get a good result on Duo. Here's the setup I'd use, built entirely on features that are live in RevenueCat Paywalls right now.

1. Preview your paywall on iPhone Duo in the paywall editor

The RevenueCat paywall editor now includes an iPhone Duo preview. You can switch between open and closed, portrait and landscape. The preview matches the Duo's screen shape, safe areas, and camera, and it shows your paywall as it looks in an app built with Xcode 27.1. It's the fastest way to spot problems before you open Xcode.

2. Build with Xcode 27.1 and open the Duo simulator

Install Xcode 27.1, choose iPhone Duo in Device Hub, and use the controls at the bottom of the simulator to open, close, rotate, and fold it. Walk your paywall through every posture above before you change anything, so you know what you're actually fixing.

Get the versions exactly right

Use Xcode 27.1, and make sure your simulator runs iOS 27.1, not iOS 27. I learned this one while setting up my own test project, so double-check both before you start.

If you present PaywallView in SwiftUI, Xcode Previews can help too. The canvas overrides picker now has a Display group for previewing content on the device's other display.

3. Present your paywall in a sheet

A sheet does a lot of Duo work for you. On the inner display, the system centers it by default. When the device is partially folded, the sheet slides away from the fold on its own.

The simplest option is RevenueCat's presentPaywallIfNeeded modifier. It checks the entitlement for you, presents the paywall in a sheet, and dismisses it once the entitlement is active. On iPad, it shows the paywall in a modal that's roughly iPhone-sized.

If you want more control, present PaywallView yourself in a .sheet. Just make sure to check the placement of your close button when you do so (see "Check your close button" above).

4. Give your content a maximum width

On the open, inner display, a paywall built for a phone can stretch edge to edge. Set your main content stack to Fill, then give it a Max width so it stops growing on wide screens. Min/max sizing needs purchases-ios 5.93.0 or later; older SDKs ignore the limits. You can also ask the Paywall AI Editor to make your paywall look good on iPhone Duo. For a design walkthrough with starting values, see Designing RevenueCat Paywalls for both iPhone Duo displays.

5. Run the checklist

Before you ship, walk your paywall through every posture and check:

  • Close is reachable and doesn't collide with the camera or the side bar
  • Close and Back show up as system controls, in the side bar on the closed display
  • The call to action is visible without scrolling on the closed, landscape screen (or you've made peace with the scroll)
  • Nothing tappable, and no price or trial term, sits on the fold when partially folded
  • The inner display in landscape doesn't look stretched
  • Select a package, fold, and unfold — your selection is still there
  • It still looks right on a regular iPhone and iPad

Ship it

You can submit iPhone Duo-optimized apps in App Store Connect today. Starting April 2027, any app you submit will need to include iPhone Duo screenshots, so it's worth capturing your app on both displays now. App Store Connect also has a new preview tool that shows how your screenshots and product page look on iPhone Duo before you submit.

Why native paywalls help here

This is the part I'm most excited about: RevenueCat Paywalls render natively on iOS, and PaywallView is a regular SwiftUI view. That's why everything in this guide works with Apple's own tools. You present it in a system sheet, swap its close button for the system one, and let iOS move it out of the fold.

Someone who just unfolded a brand-new phone is going to notice a paywall that wasn't built for it. Make sure yours was.

What's next

We're actively working on making RevenueCat Paywalls even better on iPhone Duo and other foldable devices, and this guide will grow as that work ships.

Changelog

  • October 24, 2026: Added Use system navigation for close and back buttons (purchases-ios 5.98.0) and min/max sizing, and updated for iPhone Duo going on sale.
  • October 6, 2026: Updated for Xcode 27.1, App Store submissions opening for iPhone Duo, and the April 2027 screenshot requirement. Added the close button section and the toolbarVerticalBehavior(.disabled) quick fix.
  • September 28, 2026: First version. Covers postures, Apple's guidance, the Duo preview in the paywall editor, and presenting your paywall with a native Close button.

Thank you

Huge thanks to the Paywalls team for all the work they've been putting into foldables. If you've built a Duo-ready paywall with RevenueCat, I'd love to see it! Send it my way on X @austnstuff, or to austin.blake@revenuecat.com.

Further reading