Fits Duo
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iPhone Duo goes on sale Oct 23, 2026. Developers are likely to update their apps then, so statuses are for reference until launch.

Release day, your time1 day 04:14:12

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Substack

Substack, Inc.Social

View in the App Store
On iPhone Duo

Partly fits

Substack uses most of the inner screen, but not all of it.

Its latest version is built with the iOS 27.0 SDK.[1] The iOS 27 SDK fills most of the inner display, and the iOS 27.1 SDK fills all of it.[2]

How we know
From the app’s build
Checked on
Version 3.21.0
Build
iOS 27.0 SDK
Latest version
3.21.0
Status updated

What owners report

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Sources

  1. App Store build, version 3.21.0

    Built with the iOS 27.0 SDK. Uses none of Apple’s iPhone Duo APIs.

  2. Apple Developer: Prepare your app for iPhone Duo
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