Apple
just released iOS 11.3, and among other things, the updated includes a
new tool to tell you whether or not your aging iPhone battery needs to
be replaced.
This is Apple's
response to their slowing the iPhone operation to save battery life.
Well, this new utility will examine the life expectancy of the battery
and whether its time to get the battery replaced.
Install
iOS 11.3 in Settings > General > Software Update on your iPhone.
The battery life measurement will examine whether the battery
performance is still at peak performance or throttled capacity due to
age and reduced capacity. The user can temporarily turn off the
performance management in favor of faster operation.