As rumors surrounding Apple’s highly anticipated “iPhone XX” (slated for the iPhone’s 20th anniversary in 2027) begin to surface, the tech world is buzzing about a revolutionary portless, quad-curved design. However, for hardcore Xiaomi enthusiasts, this “groundbreaking” Apple innovation is actually a blast from the past. The design Apple is preparing to unveil is essentially the exact same U4 (MIX Waterfall) concept that Xiaomi developed five years ago and eventually shelved.
We actually saw this coming months ago. On December 30, 2025, we reported that Apple is following Xiaomi’s lead, bringing quad-curved screens to the iPhone. Now, the latest industry leaks are validating that exact claim.
The Rise and Fall of the Xiaomi U4 (MIX Waterfall)
To understand what Apple is building, you have to look at what Xiaomi already built. From 2021 until mid-2022, Xiaomi engineers intensely developed the U4 prototype. As seen in the leaked hands-on images, the device featured an astonishing 88-degree quad-curved waterfall display. The screen literally cascaded over all four edges, eliminating the need for a physical metal frame, physical buttons, or charging ports.
But why didn’t it reach the mass market? As we detailed in our deep dive on what happened to the Xiaomi Quad-Curved Display Concept phone, the technology of the time simply couldn’t support the vision.
Bending glass flawlessly across four corners drove manufacturing costs to astronomical levels. Furthermore, without a metal frame, drop durability was practically zero—which is exactly why the leaked prototype images show thick, black protective bumpers on the four corners of the glass. Combined with the immature under-display camera (UDC) technology of the era, Xiaomi made the logical decision to officially shelve the project in mid-2022.
What Will Apple Do Differently 5 Years Later?
Apple is picking up the baton right where Xiaomi left it. By the time the iPhone XX launches, material science and technology will have caught up to the MIX Waterfall’s ambitious design:
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Durability Solved: Advancements in Apple’s Ceramic Shield glass and internal titanium chassis structures will likely address the extreme fragility that plagued Xiaomi’s four-corner glass design.
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A Truly Portless Ecosystem: The MagSafe ecosystem has matured enough to completely replace the physical charging port, fulfilling the vision of a seamless, interactive glass slab.
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Invisible Sensors: Apple’s under-display Face ID and camera sensors are expected to be fully mature by 2027, allowing for an uninterrupted 100% screen-to-body ratio without a notch or Dynamic Island.
When Apple eventually takes the stage to present the iPhone XX as a masterclass in modern design, it will undoubtedly be a spectacular device. But tech history will remember that this portless, buttonless, all-glass vision was first conceptualized, tested, and held in the hands of Xiaomi engineers half a decade prior.
