For models from 5th to 8th generations and for iPhone X battery your iPhone will show the battery health. However, for XS, XS Max and SE 2020 batteries this feature will not be available. After replacing your battery, the phone will display “Service” in the Battery Health feature suggesting checking the phone by an authorized service provider. Rest assured that your phone and the battery work properly despite the “Service” sign and not showing the battery health. This feature was brought by iOS for the X iPhone generation for any battery replaced by anyone except an authorized service provider.