A concertina whose bellows follow the Duo's fold
Does Foldeon work on iPhone Duo?
Yes, the developer says so: Foldeon 1.1, released October 7, 2026, adds iPhone Duo hinge controls. Fold the phone to pump the bellows; closed, you work them by touch on the cover.
- App Store confirmedBalazs Pinter, the developer, in the App Store description and the release notes for version 1.1 (released October 7, 2026), which add bellows worked by the hinge on iPhone Duo with iOS 27.1 or later. The developer's own page for the app still describes version 1.0, without the hinge.
Adapted for the fold
- Closed · Outer display
Touch bellows on the cover
Closed, the bellows switch to touch, so you can keep playing on the cover.
- Book · Partly folded
Fold to set the pace
Open and close the phone gently to pump the bellows; in Demo, that sets the pace of the tune. The big keys sit near your grip.
About Foldeon
Foldeon is Balazs Pinter’s pocket concertina, with melodies to follow and free play. Since version 1.1 the Duo’s fold works the bellows; on the cover, and on other iPhones and iPads, you drag them by touch. In Demo the app plays the notes and your movement sets the pace. Balazs Pinter also made PaperDuo.
Evidence reviews
What we checked, when, and what the evidence establishes. Each record preserves the support label at that check.
· App Store page reviewed
App Store confirmed · iphone-duo
The App Store description mentions iPhone Duo: "Designed for iPhone Duo." (version 1.2, released October 19, 2026).
App version: 1.2.
Store text only: we haven't seen the app running, and the store page doesn't show how each pose is used.
View reviewed evidence ↗· Developer statement reviewed
Developer claimed · iphone-duo
Read the App Store description and the release notes for version 1.1 (released October 7, 2026), which add hinge input on the Duo and touch controls on the cover.
App version: 1.1.
The four App Store pictures show the instrument on ordinary iPhone and iPad screens, not on a Duo. The developer's page for the app describes version 1.0, which has no hinge input. No build was tested.
View reviewed evidence ↗
Related guides
iPhone Duo poses: closed, open, book, standing and Split View
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Every iPhone app opens on iPhone Duo, but only updated ones fill the inner display. What an app looks like before its developer adapts it, how to tell which are ready, and which popular apps have said so.
Is this your app?
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<a href="https://foldhunt.com/apps/foldeon/"><img src="https://foldhunt.com/badges/featured-on-foldhunt.svg" alt="Featured on FoldHunt" width="220" height="54"></a>Need to update the listing? Email the editor.
Sources: Foldeon on the App Store (apps.apple.com) · Foldeon on the developer's site (version 1.0) (prompt2pixels.com)
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