Early iPhone Duo Reviews Highlight Major App Compatibility Issues Ahead of China Launch

The iPhone Duo’s biggest weakness at launch is shaping up to be app compatibility, with many popular apps failing to properly fill or take advantage of the foldable’s larger inner screen. That issue emerged clearly after Apple lifted the review embargo yesterday evening, allowing tech bloggers and media outlets to publish their first full hands-on assessments ahead of the phone’s mainland launch tomorrow.

Chinese tech creator He Tongxue said roughly 80 percent of the 25 commonly used third-party apps he tested had not been fully adapted for the Duo. On the unfolded inner screen, some apps simply remain centered at roughly the same size as on the outer display, leaving large unused areas instead of taking advantage of the bigger screen.

WeChat is among the most noticeable examples. In current testing, it does not properly fill the inner screen or make full use of the Duo’s sidebar layout, meaning users do not get the tablet-like experience they might expect from opening a foldable phone. Some banking, travel and other apps also show black borders, stretched interfaces or awkward layouts.

Tim Pan and his MediaStorm team reached a similar conclusion after testing the Duo’s everyday software experience. They grouped third-party apps into three broad categories: those that work but still show black borders or overlapping interface elements; those with little or no optimization, sometimes producing major display problems; and a smaller group, including iQIYI and Feishu, that already make effective use of the larger screen. Bilibili, for example, has adapted video playback for the Duo’s 4:3-style viewing experience.

MediaStorm also put more emphasis on the hardware. Its stress tests found that the hinge remained smooth after more than 10,000 folds, including testing at minus 20 degrees Celsius, although the screen crease became more visible. A reverse-bending test also suggested the body is structurally strong.

That reflects a broader theme in early reviews: Apple appears to have done much of the difficult hardware work well, including the hinge, thin body and relatively shallow crease, but the software experience remains uneven. International reviewers have raised similar concerns, particularly around limited multitasking and inconsistent third-party app support compared with more mature Android foldables.

Apple is already pushing developers toward Duo support. The company says developers can submit Duo-optimized apps now, and starting in April 2027, newly submitted apps and games will be required to include iPhone Duo screenshots. Apps built with the newer SDK can take fuller advantage of its unusual inner and outer displays.

That requirement does not mean every existing app will suddenly be fully optimized in April, but it gives developers a clear deadline to begin supporting the device more seriously.

For buyers considering the 15,999-yuan (US$2,250) foldable, the early consensus is therefore relatively simple: The hardware feels much closer to a finished product than many first-generation devices, but software compatibility may take months to catch up. With scalpers already asking premiums of several thousand yuan, early adopters are effectively paying not only for Apple’s first foldable, but also for a still-developing app ecosystem.