Slack

Confirmed by Apple as optimized for iPhone Duo's inner display and Split View at launch.

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Slack is one of the three third-party apps Apple has publicly confirmed will be optimized for iPhone Duo at launch, alongside Netflix and Zoom.

This listing is based on publicly confirmed information, not hands-on testing — iPhone Duo pre-orders open October 16, 2026, with the device shipping October 23. We will publish a full review once we have tested Slack on real hardware.

What is confirmed

Slack has adopted the iOS 27.1 SDK required to fill iPhone Duo's inner display, rather than falling back to the boxed-in compatibility mode older apps use
It supports iPhone Duo's fixed 50/50 Split View, so a channel and a huddle, or a channel and Notes, should be able to run side by side
Apple has said apps built on the scene-based lifecycle required by iOS 27 handle the fold and safe-area changes automatically, and Slack is named among the apps that qualify

What we do not know yet

Slack has not published its own feature page for iPhone Duo as of this writing, so details on huddle behavior in Split View or whether the outer display can show unread counts are unconfirmed. We will update this listing after our hands-on review.