PSPDFKit requires the modern
UIViewControllerBasedStatusBarAppearance mode introduced in iOS 7 to be set to
YES in your Info.plist file. This is the default setting and uses the modern view controller based API for status bar manipulation. The older,
UIApplication-based API is deprecated in iOS 9 and is unavailable when compiling extensions.
If your application uses the legacy API, you need to migrate your code to the new view controller based one, else PSPDFKit will not be able to manage the status bar for you. We detect this issue and show a warning dialog for debug builds.
In PSPDFKit 3.x we tried supporting both modes, but they are too different and Apple clearly explained that view controller based status bar management is the future and that using global state to manage the status bar is a "Bad Idea", so we fully focus on the new API to deliver a superior product.
You can learn more about this in Apple's Transitioning Guide.
If everything works as intended and all you want to do is to disable the warning, set
PSPDFKit.sharedInstance.setValue(true, forKey: "com.pspdfkit.development.suppress-warning-alerts")
Note that we only present the warning during development, so this actually doesn't change anything in production-builds.