iPhone Duo App Store submission

The two displays

iPhone Duo is a book-style fold with two screens you design for separately. The outer cover is a 5.4″ Super Retina XDR display at 1398×2034 and 460 ppi. The inner folding OLED is 7.6″ at 1878×2670 and 430 ppi.

Those pixel counts are hardware specs from Apple’s Duo specs page. They describe the panels, not an App Store Connect screenshot upload size. Do not treat 1398×2034 or 1878×2670 as a new ASC slot until Apple publishes one.

Folded, the cover behaves like a small iPhone. Open, the inner display is a wide tablet-like canvas. Layout, safe areas, and which flow the reviewer sees first will differ between those two states.

What to prepare before ASC publishes a Duo slot

Design for cover and inner. If a primary flow only works on one of the two displays, say so in Review Notes and show how a reviewer reaches the other state.

Keep your current 6.9″ iPhone screenshot set. App Store Connect still needs that required family until Apple adds Duo uploads. Do not drop the 6.9″ set because a foldable shipped.

Document folded vs open flows. Note which screens are cover-only, which need the inner display, and any rotation or split-view behavior.

Do not invent review claims about Always-On or HDR. If the shipping binary does not show that behavior, listing copy and Review Notes should not promise it.

What usually does not change

Privacy nutrition labels still have to match the binary and its SDKs. A foldable display does not create a new data type.

If the app creates accounts, in-app account deletion is still required. Duo does not move that to a website-only flow.

In-app purchase and Small Business Program terms are unchanged by this hardware. EU storefront rates are a separate map.

Guideline 4.2 (minimum functionality) still applies. A cover widget or a thin inner webview is not a new exception.

Guideline 2.1 (app completeness) still applies. Screenshots, previews, and Review Notes have to match the build a reviewer installs.

Indie checklist before 23 Oct

Duo is available 23 Oct (pre-order 16 Oct). You can still submit on today’s devices. Work this list so a foldable launch week does not force a metadata scramble.

• Cover (5.4″, 1398×2034) and inner (7.6″, 1878×2670) layouts both work — book-style fold
• Review Notes explain folded vs open paths a reviewer can follow
• Current 6.9″ screenshot set stays uploaded; no invented Duo ASC pixel sizes
• Listing copy and notes do not claim Always-On or HDR unless the binary shows it
• Privacy nutrition labels still match the app and SDKs
• In-app account deletion still present if the app creates accounts
• IAP / Small Business Program unchanged by Duo hardware
• Guideline 4.2 minimum functionality still holds on cover and inner
• Guideline 2.1 completeness — screenshots and notes match the shipping build
• Watch developer.apple.com and App Store Connect for a published Duo screenshot slot