The fourth developer beta of iOS 27 has references to an iPhone with two batteries, according to Macworld. New Battery Health strings include mentions of multiple internal batteries, instead of a single battery. MacRumors confirmed the mentions are in the beta.

  ●"The batteries in this iPhone are performing as expected."

  ●"The health of the batteries in this iPhone has significantly degraded. An Apple Authorized Service Provider can replace the batteries to restore full performance and capacity."

  ●"The health of the batteries in this iPhone has significantly degraded, and one of the batteries could not be verified as a genuine Apple battery. An Apple Authorized Service Provider can replace the batteries to restore full performance and capacity."

All of the wording in the Settings app on current iPhone models references a single battery, so the plural phrasing is curious.

Macworld speculates the wording references the foldable "iPhone Ultra" Apple is working on. Prior rumors suggest the ‌iPhone Ultra‌ will use two battery cells with 1,921mAh and 2,962mAh capacities for a total of 4,883mAh. Foldable smartphones typically have two batteries, with one located in each half of the device. Apple is likely to use the same design.

The ‌iOS 27‌ strings suggest the batteries in the ‌iPhone Ultra‌ could be serviceable separately, so a single failing cell could be swapped on its own. An option to replace a single degraded cell could lower repair costs.

Apple's ‌iPhone Ultra‌ is expected to debut this September alongside the iPhone 18 Pro models.

Source: Macrumors