Apple caused quite an uproar with customers when it was discovered that the company released software back in 2016 that slowed down older iPhones to prevent problems with the aging lithium ion batteries on these phones. Now, Apple is working to appease customers with an upcoming update coming to iOS. Version iOS 11.3 will get a recommendation or notice if the battery needs to be serviced. (Apple recently cut the price of replacing an iPhone battery from $99 to $35.) You will also see if the power management feature is on for your device and you’ll get the option to turn this off. iPhone 6, iPhone 6 Plus, iPhone SE, iPhone SE, iPhone 6s, iPhone 6s Plus, iPhone 7, and iPhone 7 Plus users will find this feature in the Battery section of the Settings menu. iOS 11.3 is set to arrive in the spring but the beta release will be coming soon. It must be noted that the new battery feature is coming at a later beta release.
Source: CNET