https://www.techradar.com/news/apples-iphone-battery-replacement-credit-atones-for-batterygate

You may have found money waiting for you, or at least credit at the Apple Store, as Apple is making further amends for purposely slowing down older iPhones with deprecated battery life.

It's offering a $50 (£54) credit to anyone who paid full price for a battery replacement between January 1, 2017 and December 28, 2017 on an iPhone 6 or later. Of course, the replacement had to have been done at the Apple Store or an authorized retailer.