Apple has just released the fourth developer beta of iOS 27, and buried deep inside the update is what may be one of the clearest references yet to the company’s long-rumored foldable iPhone.
Macworld discovered new Battery Health strings referencing an iPhone with multiple internal batteries, a setup no current iPhone has, but one that would make a lot of sense for a foldable device.
iOS 27 lays the groundwork for Apple’s foldable iPhone
The new code strings explicitly state that they are intended for a multi-battery iPhone, alongside the existing references to single-battery iPhones (emphasis ours): “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. Rather than referring to a single battery, as every current iPhone does. Apple now explicitly talks about “the batteries in this iPhone” and even mentions a situation where “one of the batteries” may not be a genuine Apple part.
The folding iPhone Ultra is expected to utilize a dual-battery system, with separate batteries on both sides of the display.
Foundry
On its own, that might not sound like much. After all, it’s not likely that Apple is going to suddenly shove two batteries into an iPhone Pro Max. But given the rumors that Apple’s expected to reveal its first foldable iPhone this fall (the so-called iPhone Ultra), the idea of adding dual-battery support suddenly makes a whole lot of sense.
Once again, no shipping iPhone today would ever trigger these strings. Every current model contains a single battery, making the new “multi-battery” wording difficult to explain unless Apple is actively developing hardware with a different internal architecture.
Furthermore, this isn’t the first time we’ve found evidence in iOS pointing toward a foldable iPhone. The first iOS 27 beta already included references to angle detection and fold states, suggesting Apple is prepping to support a folding display. The company has also been encouraging developers to get their apps ready to run on multiple screen sizes.
Separately, reliable supply chain reports have consistently claimed that Apple’s first foldable iPhone will use a dual-cell battery design. That’s hardly surprising, since nearly every book-style foldable smartphone splits its battery into two separate cells (one on each side of the hinge) to 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 and the increasingly consistent reports from the supply chain, 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.
