Apple admitted to implementing a power management feature which slows processor speeds in older iPhones in order to extend battery life.

In a statement to TechCrunch, Apple said it aims to give customers the best experience possible and in 2016 rolled out a feature which evens out peaks in performance to ensure old batteries don’t get overwhelmed.

“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. Last year we released a feature for 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,” it explained.

The company added the feature is also live on iPhone 7 devices with iOS 11.2 and noted it plans to enable the feature on other products in the future.

Apple issued its statement after users on Reddit highlighted a slowdown in processing on older iPhones. One user illustrated the difference on Twitter:

As noted in the Twitter post, there’s no need to upgrade devices to avoid the lag. The slowdown in performance can be fixed with the insertion of a fresh battery into older iPhones.