The fourth developer beta of iOS 27 has been released by Apple, containing what may be one of the clearest references yet to the company's long-rumored foldable iPhone.
New Battery Health strings referencing an iPhone with multiple internal batteries have been discovered, a setup no current iPhone has but one that would make a lot of sense for a foldable device.
The new code strings explicitly state that they are intended for a multi-battery iPhone, alongside the existing references to single-battery iPhones: "The batteries in this iPhone are performing as expected," reads one of the strings. Another mentions that "the health of the batteries in this iPhone has significantly degraded."
The wording is notable, as it refers to "the batteries in this iPhone" rather than a single battery, as every current iPhone does. This suggests that Apple is actively developing hardware with a different internal architecture, one that could support a foldable design.
The idea of adding dual-battery support now makes a lot of sense, given the rumors that Apple's expected to reveal its first foldable iPhone this fall. The iPhone Ultra is expected to utilize a dual-battery system, with separate batteries on both sides of the display.
No shipping iPhone today would ever trigger these strings, as every current model contains a single battery. The new "multi-battery" wording is difficult to explain unless Apple is actively developing hardware with a different internal architecture. This isn't the first time we've found evidence in iOS pointing toward a foldable iPhone, and the company has also been encouraging developers to get their apps ready to run on multiple screen sizes.
Reliable sources have consistently claimed that Apple's first foldable iPhone will use a dual-cell battery design, a setup that would make better use of the limited internal space. As always, software references aren't a guarantee that a feature or product will ultimately ship, but taken together with the growing number of foldable-related discoveries inside iOS 27, the evidence continues to point in one direction.
We're still two months away from the likely official announcement of the first foldable iPhone, but all signs are pointing to an imminent release.
