Methodology
How we decide.
Every status on WorksOnDuo is a claim about how an app looks on iPhone Duo’s inner display. Here’s what each one means and what we need before we make it.
Last updated September 21, 2026
Statuses
| Status | Meaning |
|---|---|
| Built for Duo | Full screen, with layouts or features designed for the fold. |
| Full screen | Fills the inner display. No Duo-specific features yet. |
| Partly adapted | Uses most of the inner display, with some empty space. |
| Black bars | Runs in a phone-sized window with black borders. |
| Not confirmed yet | No reliable information yet. Seen it? Tell us. |
We describe the inner display only. On the outer display every iPhone app behaves as it does on any other iPhone, and every app can take part in Split View automatically.
Evidence and confidence
No app leaves “Not confirmed yet” without at least one piece of public evidence. We record the strongest source on each page:
| Confidence | What it means |
|---|---|
| Verified on device | We checked it ourselves on an iPhone Duo. |
| Developer confirmed | The developer said so publicly or in release notes. |
| Shown by Apple | Apple demonstrated or described this app on iPhone Duo. |
| Community reports | Several consistent, reviewed reports from iPhone Duo owners. |
| From release notes | Inferred from the app's release notes; not yet seen on device. |
| No evidence yet | Nobody has confirmed how this app behaves on iPhone Duo. |
Rules we follow
- No guessing. Before iPhone Duo ships on October 23, 2026, most apps are “Not confirmed yet”. We don’t infer a status from an app’s popularity, its developer or its minimum iOS version.
- Release notes flag, people decide. Our daily scan flags release notes that mention iPhone Duo. A person reviews the flag before a status changes.
- Owner reports need agreement. We need several consistent, reviewed reports — ideally with screenshots — before marking a status from the community.
- Negative statuses need evidence too. We don’t label an app “Black bars” without a report or test showing it.
- Everything is dated. Each page shows when it was last checked and keeps a history of status changes.
- Money never changes a status. Sponsorship, if any, is labelled and has no effect on the data.
Which apps we track
The US App Store’s top free, top paid, top grossing and top free games charts, refreshed daily, plus a hand-picked list of apps people are most likely to ask about (banking, social, streaming, productivity, AI assistants and popular games). Once an app has a page, we keep it. Missing one? Ask us to track it.
Facts from the App Store
App names, icons, developers, versions, release notes, and whether an app has an iPad version come from Apple’s public App Store data. “iPad version” means the developer ships a layout for iPad, not just the compatibility mode every iPhone app gets.
Corrections
Developers and owners can submit a correction or email us. We aim to respond within 48 hours and note the change in the app’s history.