The fourth developer beta of iOS 27 contains code references to an iPhone equipped with two batteries. New Battery Health strings mention "multiple internal batteries" and "the batteries" in the plural, a departure from current iPhone models which reference a single battery.

These pluralized references are fueling speculation, particularly from Macworld, that they pertain to the rumored foldable "iPhone Ultra." Previous reports suggest the iPhone Ultra will indeed feature two battery cells, with capacities of 1,921mAh and 2,962mAh, totaling 4,883mAh. This dual-battery design is common in foldable smartphones, where one battery is typically housed in each section of the device.

The iOS 27 strings also imply that the batteries in the iPhone Ultra could be serviced independently. This suggests that a single degraded battery cell could be replaced on its own, potentially reducing repair costs for users. The iPhone Ultra is anticipated to launch in September, alongside the iPhone 18 Pro models.