iOS 27 update may temporarily drain iPhone battery, Apple says

Apple is releasing iOS 27 to qualifying devices on Monday, and the company says users may notice their iPhone or iPad battery draining faster than usual in the days following installation. The temporary impact is part of the setup process, which includes indexing files, downloading new assets and updating apps, according to Apple’s support page.

The update marks the second major release under Apple’s new naming system. Last year, the company skipped from its previous numerical pattern to iOS 26 instead of the expected iOS 19.

iOS 27 requires several gigabytes of space, and a lack of storage could prevent some users from installing it.

“Immediately after completing an update, particularly a major release, you might notice a temporary impact on battery life and thermal performance,” Apple says. “This is normal, as your device needs time to complete the setup process in the background, including indexing data and files for search, downloading new assets, and updating apps.”

The impact typically lasts only a few days while the device completes behind-the-scenes work. Apple also notes that user behavior plays a role, and exploring new features can contribute to faster battery drain.

Experts and phone manufacturers generally advise charging only to 80% to prolong battery life.