The iPhone Duo is Apple's first foldable iPhone: a 7.6-inch inner display, a 5.4-inch outer display, and iOS 27. Apple announced it on September 9, 2026, and it went on sale on October 23. Most of what feels new about it comes from the two displays, and the settings that matter most are about those displays: why some apps sit in a small window, how much text fits, and what belongs on which screen. Notifications, Focus and Screen Time work as they do on any iPhone, so this guide covers them in one paragraph and points to the longer one.
1. Fix apps that look small
This is the display setting that changes the most, and it lives in the App Store, not in Settings. Apple's developer guidance says apps built with the iOS 26 SDK or earlier run on iPhone Duo but do not adapt to every layout. When the phone is open, such an app sits in the center of the display with empty space around it. Apps built with the iOS 27 SDK resize to fill most of the inner display, and apps built with the iOS 27.1 SDK or later extend to the full display. Apple's newsroom says apps optimized for the Duo carry a Made for iPhone Duo badge on their product pages.
That gives three tiers, and you can sort your own apps into them in a few minutes:
- Floating in the middle: built with the iOS 26 SDK or earlier. The app works, but it does not use the whole display.
- Filling most of the display: built with the iOS 27 SDK.
- Edge to edge: built with the iOS 27.1 SDK or later.
Open the App Store, update everything, and then open the apps you use every day with the phone unfolded. If one still floats in a small window after an update, no phone setting will fix it. The fix is a newer build from its developer, and the useful thing you can do is check again after the next update. Our guide to which apps fit the iPhone Duo inner display goes through the eight biggest social apps one by one. If a video fills only part of the screen, the YouTube black bars guide explains why.
2. Set text and display size on the inner display
A 7.6-inch display can show far more on one screen than a normal iPhone, and the default sizes may not suit how you hold it. iOS has text size and Display Zoom controls under Display & Brightness in Settings on iPhone generally, and the inner display is a good place to try them. Open the phone, open a long article or a messages thread, and ask one question: do you want more on the screen, or the same amount, larger and easier on the eyes?
Two habits help. First, change the setting while you are looking at real content, not the Settings screen, so you see the effect on text you actually read. Second, judge it after a day. A tighter layout looks impressive in the first minute and tiring by the evening. This is a preference, not a rule, and it is worth revisiting after an app update changes how an app fills the display.
3. Decide what goes on which screen
Apple describes the 5.4-inch outer display as the screen for one-handed use that fits in a pocket, and the 7.6-inch inner display as the large canvas for entertainment, gaming and multitasking. Nothing in Settings enforces a split, but you can adopt one and make it concrete (the seven-day productivity test turns this into an experiment with your own Screen Time numbers):
- Outer display: tasks that end. Messages, maps, a call, the time, a quick look at a calendar.
- Inner display: deliberate, longer use. Reading, writing, a film you chose, two apps side by side.
The inner display is where Split View lives; Apple says it lets you open two apps side by side on iPhone for the first time. What you pair matters more than the feature: a notes app next to a document helps, two feeds next to each other do not. The full list of what Apple says multitasking includes is in our iPhone Duo split screen guide.
4. Arrange Today View and the Dock
When the phone is open, Apple says the display shows two Home Screen pages, with Today View, a vertically scrolling list of customizable widgets, on the left. Apple also says the Dock, Lock Screen controls and app navigation move to the side to save vertical space. That changes where your thumb lands, so arrange the layout on purpose instead of letting it settle by accident.
Use the Today View column for things you check deliberately: calendar, weather, reminders. Put tools on the first page and move social apps to a folder on a later page, or reach them through search. The icon your thumb finds by reflex is the one that opens most often, so the first page should hold tools. Our iPhone Duo tips and tricks guide has more on laying out the two pages.
5. Set up the outer display for one hand
With the phone closed, Apple's developer guidance says the outer display shows an app's content next to the status bar and camera, and that apps built with older SDKs do not adapt to every layout. In practice the outer display is where small, finished jobs belong, so set it up for them. Keep the apps you open with one hand, such as messages, maps, camera and payments, easy to reach, and leave long reading and video for the inner display.
It also helps to treat the outer display as the place where a feed has to earn its minutes. If you check a social app at all, doing it on the small screen for a few minutes is easier to stop than an hour on the large one. For what the closed phone is good for, see what you can use the outer display of the iPhone Duo for.
6. Choose defaults for feed apps
A 7.6-inch display shows more of a feed per swipe, brighter and larger, and that makes it easier to stay in. There is no switch for this in the Settings app, so the answer is to change what the app shows you. Stillfeed is an iPhone app that does this. It is an in-app browser that loads Instagram, YouTube, X, Reddit, TikTok, Snapchat, LinkedIn and Facebook and hides their endless and recommendation feeds on your device before they render. The native apps are not modified. Removing the feeds is free from first launch, with no account, sign-up or trial. These are the free defaults: Reddit is the clearest case; see Reddit on a bigger screen.
- Instagram: Reels and Explore removed, opens to the Following feed. How the app itself fits the screen: how Instagram looks on iPhone Duo.
- YouTube: Shorts removed; search, subscriptions and regular videos stay.
- X: the home timeline opens on Following instead of For You, and Explore trends are hidden.
- TikTok: For You and Discover removed, opens to Following.
- Reddit: r/popular and r/all blocked, home feed sorted by New.
- Snapchat: Discover and Spotlight blocked, so it is chat only. See keeping Spotlight out of Snapchat on iPhone Duo.
- LinkedIn: People You May Know and games removed; feed, jobs and messaging stay.
- Facebook: a Block Reels switch, on by default. The Facebook feed itself is not removed.
Stillfeed is not a Screen Time app and does not block whole apps. It keeps messages, profiles, search and posts from people you follow. For platform steps on the Duo, see Instagram on iPhone Duo, YouTube Shorts on the iPhone Duo and the X setup checklist.
Notifications, Focus and Screen Time
These three are ordinary iOS features that Apple documents for iPhone in general, and they are not specific to the Duo. A notification summary, a scheduled Focus and one Screen Time limit are worth setting on day one, and our iPhone Duo tips and tricks guide walks through each with the Apple sources.
Common questions
Why does an app look small on the iPhone Duo inner display?
According to Apple's developer guidance, apps built with the iOS 26 SDK or earlier do not adapt to all layouts and appear in the center of the open display. The fix is an update from the app's developer, not a phone setting.
Which iPhone Duo display settings are worth changing first?
Update your apps so they fill the inner display, then try text and display size on real content, decide what goes on each screen, and arrange the two Home Screen pages. For the notification, Focus and Screen Time settings, see the tips and tricks guide.
Are these settings specific to the iPhone Duo?
The display-fit behavior, the two Home Screen pages and the outer display are specific to the Duo. Text size and Display Zoom are standard iOS controls that Apple provides on iPhone generally.
Which display should I use for social apps?
If you use a feed at all, the outer display suits a few minutes and the inner display suits a longer session, which is easy to overdo. Choosing one screen per app and sticking to it is more reliable than judging in the moment.
Do I need Stillfeed Pro to remove the feeds?
No. The feed removal listed above is free from first launch. Pro is an optional subscription that adds time and focus tools and extras such as word filters; its prices are shown in the App Store.
Sources
- Apple Newsroom, Apple unveils iPhone Duo (September 9, 2026): display sizes, iOS 27, Split View, Today View and the two Home Screen pages, October 23 availability, Made for iPhone Duo badge.
- Apple Developer, Three steps to make your app shine on iPhone Duo: behavior by SDK version on the open and closed displays.
