Mozilla's web browser. No iPhone Duo version announced yet.
Does Firefox work on iPhone Duo?
Not announced yet. Mozilla hasn't said when Firefox will get an iPhone Duo layout. It still opens on the Duo, but won't fill the inner display until it's updated.
- Not announcedNo announcement from Mozilla that we have found, and the current App Store release notes don't mention iPhone Duo.
Until it's updated
What an app does on iPhone Duo before its developer adapts it. Which of the open cases applies to Firefox depends on the tools its current version was built with, and we haven't seen it on the device.
Closed
On the outer display it looks and works as it does on any iPhone.
Open, built with older tools
An app last built with Xcode 26 sits in an iPhone-shaped window on the inner display, with black borders around it.
Open, built for iOS 27
An app built with the iOS 27 SDK resizes to use more of the inner display, with some space left over.
Open, built for iOS 27.1
Only an app built with the iOS 27.1 SDK reaches the edges of the inner display and moves its bar buttons to the side. Apple calls that “optimized for iPhone Duo”.
About Firefox
Firefox has no announced version for iPhone Duo. As of October 6, 2026, the current App Store release is version 157.1, from October 5, and its release notes don’t mention the Duo. Mozilla has made no announcement that we have found.
A browser’s own toolbars are what changes most on the Duo, and Teak has already moved its toolbar to the side. Mozilla hasn’t announced anything for Firefox, and Google hasn’t for Chrome.
Firefox will still open on iPhone Duo, like every app on the App Store. Closed, it looks as it does on any iPhone. Open, it won’t reach the edges of the inner display until Mozilla rebuilds it with Apple’s iOS 27.1 tools, which Apple only cleared for App Store submissions on October 5. The App Store lists an iPad version, so a layout for wider screens exists; nothing says the Duo will get it. More in how apps that aren’t updated run on iPhone Duo.
Know something we don't?
If Mozilla has announced or shipped a version for iPhone Duo, send us the link and we'll update this page the same day.
Sources: Firefox Fast & Private Browser on the App Store (apps.apple.com)
More for iPhone Duo
Netflix
Netflix, Inc.
Clips on the outer screen, cinema on the inner one, redesigned for iPhone Duo.
Launch partner: Named by Apple as an iPhone Duo launch partner.
- Closed
- Open
- Book
- Standing
Detail
Detail Technologies
On-device AI video creation, built on the new Core AI framework.
Launch partner: Named by Apple as an iPhone Duo launch partner.
- Open
Slack
Slack Technologies
More of Slack and more of your messages on screen at once when iPhone Duo opens.
Launch partner: Named by Apple as an iPhone Duo launch partner.
- Open