Apple Says iOS 27 Battery Drain Is Normal After Update

Apple released its annual iPhone software update, iOS 27, on Monday, September 14, 2026, and many users have since reported their devices draining battery faster and running warmer than usual. According to Apple, this behavior is a normal and temporary side effect of a major software update. The company explains that after installing a significant update like iOS 27, iPhones perform intensive background tasks to complete the setup process. These tasks include indexing data and files for system search, downloading new assets for features, and updating installed applications. This background activity consumes more power and generates extra heat, even when the screen is off. Apple states that the impact of iOS 27 is more pronounced than in previous years because the update requires a complete reindexing of the device to support new Siri AI features. This process is necessary for the enhanced on-device intelligence capabilities introduced in the update. The temporary battery drain typically lasts between 24 and 48 hours.