
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.
 
