viewIsAppearing is available in iOS 13 and above, and I understand that setting the layout in this lifecycle is a good way to do it. But when I use it, confirmed that UIKeyboardLayout does not work properly in viewIsAppearing in iOS versions lower than 16.0. There is a small problem not only with viewIsAppearing, but also with viewDidLoad(). In viewDidLoad(), the component to which UIKeyboardLayoutGuide is applied is visible when the screen first appears. However, there is a problem where the layout with UIKeyboardLayoutGuide applied is not visible when returning after changing the navigation screen (Push & Pop). I confirmed that UIKeyboardLayoutGuide is applied properly in viewIsAppearing and viewDidLoad in iOS 16.0 and higher versions. Below is the code and environment for reproducing the problem situation. ==================================================== Envirionment: M1 Pro(Sonoma v14.5), Xcode(v15.4), iPhone Simulator (iOS v15.0, v15.2) import UIKit import SnapKit final class ViewController: UIViewController { private let uiTextField: UITextField = { $0.placeholder = "search" $0.backgroundColor = .red return $0 }(UITextField()) override func viewIsAppearing(_ animated: Bool) { super.viewIsAppearing(animated) view.backgroundColor = .white layout() } private func layout() { view.addSubview(uiTextField) uiTextField.snp.makeConstraints { $0.height.equalTo(50) $0.horizontalEdges.equalToSuperview() $0.bottom.equalTo(view.keyboardLayoutGuide.snp.top) } } override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { view.endEditing(true) } } I wonder if I haven't checked what I need to check yet, or if there are other problems.