Does FirstSeed Calendar work on iPhone Duo?

Yes. FirstSeed Calendar is updated for iPhone Duo and uses the full inner display. Its latest version is built with the iOS 27.1 SDK and uses Apple’s iPhone Duo APIs.

Is FirstSeed Calendar letterboxed on iPhone Duo?

No. FirstSeed Calendar fills the inner display.

All apps

FirstSeed Calendar

Name: FirstSeed Calendar
Author: FirstSeed Inc

FirstSeed IncProductivity

View in the App Store

On iPhone Duo

Fits

FirstSeed Calendar fills the inner screen and adapts when you fold.

Its latest version is built with the iOS 27.1 SDK and uses Apple’s iPhone Duo APIs.[1]

How we know: From the app’s build
Checked on: Version 10.1.0
Build: iOS 27.1 SDK
uses Apple’s iPhone Duo APIs
Latest version: 10.1.0, Oct 17, 2026
Status updated: Oct 22, 2026

What owners report

No reports from owners yet. Add yours

Version history

Version 10.1.0Fits
iOS 27.1 SDK
Checked Oct 22, 2026

Sources

App Store build, version 10.1.0
Built with the iOS 27.1 SDK. Uses UIView.reservedRegions and systemTraitsAffectingVerticalBarEdge.