Apple says it will give iPhone users the ability to turn offa software tool that can slow down device performance.The change is expected to come this spring with the releaseof Apple's latest mobile operating system update, iOS 11.3.The announcement followed heavy criticism and user angerwhen it became public that Apple had secretly beenslowing down operating systems of older iPhones.The slowdown issue was first pointed out in internet reports.Apple admitted the practice in December.In an explanation, the company said it only took the actionto prevent some aging batteriesfrom failing and completely shutting devices down.All rechargeable batteries used in mobile devicesbecome less effective over time.Certain temperature conditions can also cause a battery to age faster.Apple said these older batteries could unexpectedly shut downduring times of high energy demand.It called such shutdowns "unacceptable"and said that is why the companytook "power management" measures to prevent them.Many people have long suspected Appleintentionally slows the performance of older iPhonesin an effort to get users to buy new ones.Apple has strongly denied this suspicion."We have never - and would never - do anythingto intentionally shorten the life of any Apple product,or degrade the user experience to drive customer upgrades," the company said.Despite this explanation, Apple was criticized for not informing iPhone ownersabout the power issues before it decided to slow devices down.Many owners argued they would have chosen to replace batteriesif they had known the issues beforehand.Several lawsuits seeking monetary damages from Applewere also started by iPhone owners.They owners argued they would not have spent money on new iPhonesif they had known there were other ways to fix slow performance.In a statement Wednesday, Apple said it had received requestsfor information about the issue from U.S. government agencies.The statement followed a Bloomberg reportthat the Department of Justice and Securities and Exchange Commissionwere looking at whether the company's actions had violated any securities laws.To answer user concerns,Apple announced it was offering owners of an iPhone 6 or laterthe chance to replace batteries at a reduced cost.The price to replace a battery was cut from $79 to $29,with the deal available worldwide through December 2018.In its announcement about the iOS 11.3 update,the company said users themselveswill be able to turn off the power management feature.In addition, a new tool will be added to show iPhone battery healthand suggest when service is needed.Apple also previewed some other new features to be releasedwith its iOS 11.3 update this spring.The update will include several new Animojis.These are animated characters iPhone X owners can use with their voicesand facial expressions to create videos and messages.In addition, a new feature in the iOS Health appis designed to organize user data from various medical facilities in one view.The Health Records feature can also be used to send messages to patientsabout conditions, medicines and laboratory results.Apple says all medical data is encrypted for user protection.The iOS 11.3 update also includes a change to Apple Musicthe company says makes it easier to play unlimited music videoswithout seeing advertisements.Also, Apple News will include new featuresto find and view the most important videos of the day.Finally, a new tool called Business Chatwill provide a way for users to directly connectwith company help representatives from within the Messages service.