Apple is explaining publicly why some people might notice their iPhones slowing down.
The company confirmed on Wednesday that it has algorithms in place to help keep an iPhone running at optimal performance -- preventing it from shutting down entirely -- if there is an older battery inside that can't keep up with the required power.
Apple was responding to a backlash after reports on Reddit suggested that the company was purposefully lowering the clock speeds, or how fast the phone's processor runs, after a few years of use.
"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices," Apple explained to CNBC. "Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components."
Apple said it introduced a feature last year for the iPhone 6, iPhone 6s and iPhone SE to "smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions."
TechCrunch first reported on Apple's response.
Apple said that feature has been extended to the IPhone 7 and will be added to "other products in the future."
Apple had to release an update for the iPhone 6 and iPhone 6s last year after users reported that their phones were shutting down unexpectedly, even if the phone still showed there was juice in the battery.