ISIT on iPhone Duo
Apple's first foldable has two screens and five ways to hold it. I mapped how a devotional app built for one tall phone would behave on each, then redesigned it to use the fold.
InSpiritInTruth (ISIT) is my devotional app. Before readers found the problems on a Duo, I researched the device, mocked every pose at true size and planned the fix.
A new phone shape, an app built for one
The iPhone Duo went on sale on 23 October 2026. ISIT was designed for one tall screen and locked to portrait. The question was what breaks when the phone opens.
What the research said
- 2
- Screens5.4″ outside at 466×678pt. 7.6″ inside at 890×626pt, hinge down the middle.
- 5
- Poses to design forClosed, sideways, open, book and tabletop. Apple says lay out by size class.
- 27.1
- SDK to fill the screenApps built earlier run letterboxed, and many don't behave yet.
From launch coverage, reviews and developer write-ups. Apple's own spec page could not be opened at the time, so the figures are as reported.
What I found
- The inner screen ignores the portrait lock, so ISIT opens sideways.
- A devotional's photo is 600pt tall on a 626pt screen. The title never shows.
- Home is a 600pt strip with the hinge through every card.
- Half-folded, the app can't tell. Half the layout lies flat on the table.
ISIT on a normal phone
One column, one tall screen. It works well here, and the outer screen barely changes it.
Before and after
Today's build against the proposed layout, every pose at true point size. Photos capped at 55% of screen height, two panes split at the fold.
