Finance v10.3.8
Does UnionPay APP work on iPhone Duo?
It works, but with black bars. UnionPay APP 10.3.8 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 10.3.8, read Oct 25, 2026
- iPad version
- No
- Phone-only layout today
- Latest version
- v10.3.8
- Oct 8, 2026
- Duo in release notes
- Not yet
About UnionPay APP
UnionPay APP is made by 中国银联 and first came out on the App Store in March 2013. It has 587 ratings on the US App Store, averaging 1.9 stars. Version 10.3.8 came out on Oct 8, 2026 and needs iOS 13.4 or later. It's free to download.
From its App Store listing:
UnionPay APP is a strategic product for integrated mobile payment in the banking sector. It provides comprehensive management of bank cards and brings together all card discounts and special offers. 【Main Features】 1. Scan-to-pay feature with UnionPay's financial-grade security protection, ensuring worry-free fund security. 【Official Website】https://www.95516.com/ 【Official WeChat】Yinlian_KY
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 UnionPay APP. 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 10.3.8 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 10.3.8 · Oct 8, 2026
Fixed known problems.
Questions
Does UnionPay APP work on iPhone Duo?
It works, but with black bars. UnionPay APP 10.3.8 is built with the iOS 26.2 SDK, so iPhone Duo runs it in a phone-sized window on the inner display.
Does UnionPay APP 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 UnionPay APP 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 UnionPay APP 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 UnionPay APP 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 UnionPay APP within about a day of its release and update this page.
What can I do about the black bars until then?
Use UnionPay APP 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.