Apple may have provided one of its strongest software clues yet that a foldable iPhone is on the way. Hidden within the latest iOS 27 Beta 4 developer release are new code strings referencing an iPhone with a multi-cell battery design—a configuration that aligns closely with the architecture used in today’s foldable smartphones.
The discovery adds to a growing body of evidence suggesting Apple is preparing to launch its first foldable iPhone, widely rumored to debut as the iPhone Ultra or iPhone Fold.
iOS 27 Code References Multiple Batteries
Following Apple’s release of iOS 27 Beta 4 to developers, Macworld analyzed the system files and uncovered new text strings within the operating system’s Battery Health module.
Unlike current iPhone models, which consistently refer to a single battery, the newly added code uses plural language throughout, including messages such as:
- “The batteries in this iPhone are performing as expected.”
- “The health of the batteries in this iPhone has significantly degraded.”
- References indicating that one of the batteries may not be a genuine Apple component.
This marks the first time iOS has explicitly included support for an iPhone featuring multiple battery cells.
Since every iPhone currently on the market uses a single-cell battery design, the appearance of these strings strongly suggests Apple is developing a new hardware platform with a fundamentally different internal layout.
Dual-Cell Batteries Are Standard in Foldable Phones
A dual-cell battery configuration is widely used across the foldable smartphone industry.
Rather than relying on one large battery, manufacturers divide battery capacity between two separate cells positioned on either side of the hinge. This arrangement allows engineers to maximize the limited internal space created by a folding chassis while maintaining a slim profile and balanced weight distribution.
If Apple adopts a similar approach, it would be consistent with the engineering solutions already used by leading foldable devices from Samsung, Google, Honor, Huawei, OPPO, and other manufacturers.
Supply Chain Leaks Point to a 5,000mAh-Class Battery
The software findings are also supported by recent supply chain reports.
Chinese tipster Digital Xiaolianzhan previously claimed that Apple’s battery supplier recently registered two new battery packs with the following rated capacities:
- 1,921mAh
- 2,962mAh
Combined, the two cells provide a rated capacity of 4,883mAh, suggesting the final typical battery capacity could fall between 4,800mAh and 5,000mAh.
For comparison:
- Google Pixel 10 Pro Fold: 5,015mAh
- Samsung Galaxy Z Fold7: 4,400mAh
If accurate, Apple’s first foldable iPhone would be competitive with current flagship foldables in battery capacity.
Foldable Features Appeared in Earlier iOS 27 Builds
This isn’t the first time iOS 27 has hinted at foldable hardware.
Developers examining the first iOS 27 beta, released after WWDC 2026, discovered new framework parameters including:
- foldState
- angleDegrees
- mechanicalAngleDegrees
These APIs appear designed to detect whether a device is fully folded, fully unfolded, or partially open while also measuring the hinge angle in real time.
Such functionality has no practical use on existing iPhone models but would be essential for enabling adaptive user interfaces, multitasking features, and app behavior on a foldable device.
Apple has also been encouraging developers to build applications that adapt more seamlessly to varying display sizes under iOS 27, another move consistent with preparations for new form factors.
Launch Expected in Late 2026
Multiple industry sources continue to point toward an autumn 2026 debut for Apple’s first foldable smartphone.
According to previous supply chain reports cited by Chinese media, Apple’s inaugural foldable iPhone is expected to be introduced alongside the iPhone 18 Pro lineup during the company’s traditional September launch event.
Apple analyst Ming-Chi Kuo has also suggested a September unveiling, although he believes customer pre-orders could be delayed until the fourth quarter of 2026, similar to the rollout strategy Apple used for the iPhone X in 2017.
Additional reports claim the device has already entered mass production at Foxconn, with development progressing despite earlier rumors surrounding hinge-related engineering challenges.
Apple’s Foldable Strategy Is Becoming Clearer
No single software string can confirm an unreleased product, and Apple frequently includes code supporting hardware that may never reach consumers. However, when viewed alongside supply chain reports, battery registrations, foldable-related APIs, and persistent industry rumors, the evidence increasingly points toward Apple’s first foldable iPhone becoming a reality.
The addition of explicit support for multiple batteries in iOS 27 Beta 4 is particularly noteworthy because it reflects hardware functionality that simply does not exist in any current iPhone.
With Apple’s annual September event only weeks away, expectations continue to build. Whether the long-rumored device ultimately launches as the iPhone Ultra, iPhone Fold, or under an entirely different name, the software and supply chain signals now appear more aligned than ever before.