Does it seem like the battery charge on your iPhone or iPad is not as long as it should?
Apple is no longer selling iPhones, but it
This feature helps to protect your phone's battery health. The built-in battery health tool allows you to see the apps and activities are the biggest drain, check your iPhone's overall battery health, and enable a low power mode to reduce certain background activity.
you need a new battery or can wring more life out of your existing one. While this feature is being released, the release of iOS 12.1 has been added to the iPhone 8 and up.