First settings to change on iPhone Duo

iPhone Duo runs iOS 27, and Apple's changes for the folding design mean some of the settings worth changing first don't exist on any other iPhone. The foldable basics already have a home in our iPhone Duo tips roundup, so they get one line each here; the rest of this guide covers battery, Always-On, Camera Control, security and two setup gotchas, with the Settings path for each.

The quick ones (covered in our tips roundup)

• Turn on Fixed Position Volume Controls in Settings > Sounds & Haptics if you want each volume button to keep one job in every orientation (details).
• StandBy can start even off the charger, and Settings > StandBy has an Only While Charging switch (details).
• If your case covers the outer display's left edge, turn on Shift Left Edge in Settings > Display & Brightness (details).
• Orientation Lock in Control Center applies only to the display you set it on (details).
• Settings > Camera > Smart Take > Flash During Capture stops the flash blinking on hands-free shots (details).
• Rest Finger to Open lives in Settings > Accessibility > Side Button (how to set up Touch ID properly).

Set a charge limit

Apple's support document says iPhone 15 and later models put charging controls at Settings > Battery > Charging, where a slider sets a limit from 80% to 100% in 5% steps. With the limit at 100%, Optimized Battery Charging can instead delay charging past 80% when it predicts a long charging session, per Apple.

iThinkDifferent describes the same Settings > Battery > Charging screen on iPhone Duo. The Duo has two batteries, one in each half, but MacRumors reports that iOS manages them as a single battery, so it appears there's one limit to set, not two.

Show the battery percentage

iClarified points to Settings > Battery > Battery Percentage, which shows the exact charge at the top of the Duo's round battery icon. Low Power Mode and other battery habits are covered in how to extend battery life.

Decide how much Always-On you want

Apple's spec page lists Always-On display for both the inner and outer displays. As of now, Apple hasn't said, in the documentation available for this guide, where the Duo's Always-On controls sit or whether you can set Always-On separately for each screen.

On earlier Always-On iPhones, the switch sits in Settings > Display & Brightness, How-To Geek notes, with options to show or hide the wallpaper and notifications. That's the first place to look on the Duo, but check what your phone actually offers. For context, Apple rates the outer display for up to 44 hours of video playback and the inner display for up to 31 hours; Apple's ratings are explained in our battery life guide.

Tune Camera Control

Apple's spec page lists Camera Control among the Duo's buttons. iThinkDifferent says Settings > Camera > Camera Control adjusts how firmly the control responds to a press, and notes the button only opens the camera.

Turn on Stolen Device Protection

Apple's Stolen Device Protection document puts the switch at Settings > Touch ID & Passcode > Stolen Device Protection, and it needs to be on before a phone goes missing. Apple says it adds a one-hour security delay before changes such as a new passcode or Apple Account password, and it requires Touch ID, with no passcode fallback, for actions like using saved passwords away from familiar locations.

Apple also says to turn it off before you sell or trade in the phone.

One setting you can't change later, and one that's in beta

Display Zoom is missing from Settings > Appearance on iPhone Duo, MacRumors reports, so the Default, Medium or Large choice made during setup sticks. An Apple Support advisor told a MacRumors forum member the only fix is to erase the phone and set it up again, and MacRumors confirmed the option is still absent in iOS 27.2. If you haven't set up yet, choose carefully: how to set up a new iPhone Duo.

Reachability arrived only in the first iOS 27.3 beta, iCulture reports, and it moves the interface sideways rather than down, under Settings > Accessibility > Touch > Reachability. That's a beta, not a public release, so the feature could change before the final release; iCulture expects the final release in December. Details are in our iOS 27.3 beta guide.

Bottom line

Most of these take seconds, and the charge limit and Stolen Device Protection are the two worth doing on day one. Not everything is adjustable yet: TapSmart notes left-handed users can't move the Dock or app controls to the left side of the outer display. For running two apps at once, see how to use Split View. Which setting did you change first?