xcode warning "estimated section footer height before ios 11" what does it mean?
You should set 0 to Estimate and implement heightForHeaderInSection:
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat { let headerHeight: CGFloat = 40 if #available(iOS 11.0, *) { tableView.estimatedSectionHeaderHeight = headerHeight return UITableView.automaticDimension } else { return headerHeight }}