How is the new way to test button.title(for: .normal) == nil and since IOS 15

Could you show the code that does not work in iOS 16 ? And tell what you get, what you expect ?

Neither button.title(for: .normal) nor setTitle(nil, for: .normal) have neen obsoleted.

To use configuration, just do this:

var configuration = UIButton.Configuration.filled()
configuration.title = "Title"  // Or nil here is you need
configuration.subtitle = "Subtitle"
configuration.image = UIImage(systemName: "swift")

let button = UIButton(configuration: configuration, primaryAction: nil)

Get sample code here: https://sarunw.com/posts/new-way-to-style-uibutton-in-ios15/

or here:

https://www.raywenderlich.com/27854768-uibutton-configuration-tutorial-getting-started

To set up depending on state resuires to write a handler:

https://sarunw.com/posts/dynamic-button-configuration/

To test title according to state:

let configuration = button.configuration

if button.state == .normal && configuration.title == nil { }