Games v4.6.1
Does Honkai work on iPhone Duo?
It works, but with black bars. Honkai 4.6.1 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 4.6.1, read Oct 24, 2026
- iPad version
- Yes
- Layout already handles big screens
- Latest version
- v4.6.1
- Sep 29, 2026
- Duo in release notes
- Not yet
About Honkai
Honkai is made by COGNOSPHERE PTE. LTD. and first came out on the App Store in April 2023. It has 53,260 ratings on the US App Store, averaging 4.4 stars. Version 4.6.1 came out on Sep 29, 2026 and needs iOS 13.0 or later. It's free to download. Among the 238 games we track on the US App Store, 34 already fill the inner display, 9 are partly adapted and 187 still show black bars. By number of ratings, Honkai is #140 of them.
From its App Store listing:
Honkai: Star Rail is a HoYoverse space fantasy RPG. Hop aboard the Astral Express and experience the galaxy's infinite wonders filled with adventure and thrills. Players will meet new companions across various worlds and maybe even run into some familiar faces. Overcome the struggles together caused by Stellaron and unravel the hidden truths behind it! May this journey lead us starward! □ Explore …
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 Honkai. 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 4.6.1 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 4.6.1 · Sep 29, 2026
Version 4.6 "Dance With the Beast Before Moonrise" is now live! New Character: Pearl (Elation: Ice) Character Rerun: Evanescia (Elation: Physical), Mortenax Blade (Nihility: Fire) New Story: Trailblaze Mission "Astropolis — Dance With the Beast Before Moonrise" New Events: "Love, Ghosts & Robots," "Interastral Peace Gala: One Take," and more New Outfits: Evanescia's Outfit "Lunar Blossoming" and Hyacine's Outfit "Warm Cotton Skies" Others: New maps, new enemies, new stages, and more
Questions
Does Honkai work on iPhone Duo?
It works, but with black bars. Honkai 4.6.1 is built with the iOS 26.2 SDK, so iPhone Duo runs it in a phone-sized window on the inner display.
Does Honkai 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 Honkai 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 Honkai 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 Honkai 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 Honkai within about a day of its release and update this page.
What can I do about the black bars until then?
Use Honkai 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.