Finance v3.65.0
Does Flex work on iPhone Duo?
It works, but with black bars. Flex 3.65.0 is built with the iOS 26.2 SDK, so iPhone Duo runs it in a phone-sized window on the inner display.
At a glance
- Inner display (7.6″)
- Black bars
- Outer display (5.4″)
- Works normally
- Built with
- iOS 26.2 SDK
- Version 3.65.0, read Oct 26, 2026
- iPad version
- No
- Phone-only layout today
- Latest version
- v3.65.0
- Oct 23, 2026
- Duo in release notes
- Not yet
On the inner display
Apps built with older SDKs are placed in a phone-sized safe area on a black background. Everything works; you just don't get the bigger screen.
In Split View
iPhone Duo is the first iPhone that can show two apps side by side, and every app takes part — including Flex. Open it on the inner display, then add a second app next to it. You can save the pair and come back to it later.
Duo-specific features
None confirmed yet. Duo-specific features include side toolbars, layouts that react to the fold, and content on the outer display while the app is open inside.
Evidence & history
App build,
Version 3.65.0 is built with the iOS 26.2 SDK
Apple runs apps built with the iOS 26 SDK or earlier in a phone-sized window on the inner display.
- : Not confirmed yet → Black bars — built with the iOS 26.2 SDK
Latest release notes
Version 3.65.0 · Oct 23, 2026
Thanks for using Flex! We update our app regularly to make your rent payment experience even better. Every update to the Flex app includes performance improvements like speed, reliability, and bug fixes. As new features are released, we'll highlight them for you directly in the app.
Questions
Does Flex work on iPhone Duo?
It works, but with black bars. Flex 3.65.0 is built with the iOS 26.2 SDK, so iPhone Duo runs it in a phone-sized window on the inner display.
Does Flex work on the outer display?
Yes. iPhone Duo's 5.4-inch outer display behaves like a regular iPhone screen, so every iPhone app works there as usual.
Can I use Flex in Split View on iPhone Duo?
Yes. On iPhone Duo every app can be placed side by side with another app on the inner display — developers don't need to opt in. How comfortable it feels at half width depends on the app's layout.
Why does Flex have black bars on iPhone Duo?
Apps built with the iOS 26 SDK or earlier run in a phone-sized window on the inner display, and iOS 27 builds can still leave some space empty. The bars disappear once the developer rebuilds the app with the iOS 27.1 SDK — you only need to update the app.
When will Flex fill iPhone Duo's inner display?
When its developer releases an update built with the iOS 27.1 SDK or later. We read the SDK of every new version of Flex within about a day of its release and update this page.
What can I do about the black bars until then?
Use Flex on the outer display, where it works like on any iPhone, or put it in Split View next to another app on the inner display so less of the screen goes unused.