Apple is set to pay up to $500 million to settle a United States lawsuit over the iPhone battery performance throttling debacle of 2018.

Via Reuters, Apple agreed to a preliminary settlement in legal documents filed on Friday. The company denied wrongdoing but said it settled to avoid lengthy court proceedings. The monetary suit is equivalent to $25 per impacted iPhone.

The lawsuit covers US owners of the iPhone 6, iPhone 6 Plus, iPhone 6S, iPhone 6S Plus, iPhone 7, iPhone 7 Plus, or iPhone SE who were running the iOS 10.2.1 operating system.

The basis of the lawsuit is that the policy changes introduced in that iOS version led customers to believe that their phones were at the end of their life, requiring purchases of new batteries or new phones altogether.

Apple rolled out the performance throttling as a feature to prevent unexpected shutdowns, as it transpired that iPhone batteries could not maintain peak performance as they aged. However, Apple rolled this out as part of iOS 10.2.1 in February 2017, without appropriately communicating the change to customers.

In Italy, Apple was forced to add a message on its website in addition to paying for a fine, apologising for poor communication of the rollout of the performance management systems.

The discovery of throttling mechanisms became a scandal as customers learned on their own about what iOS was doing to their phone. In December 2017, Apple had to officially apologise and promised changes. The company discounted battery replacements to $29 across 2018. It also introduced new Battery settings screens in iOS to show the current health of the battery inside the iPhone, and offered a toggle to disable the throttling in exchange for risk of unexpected shutdowns.

Newer iPhone models include smarter battery performance hardware to minimize the impact of throttling altogether.