At what stage of the lifecycle can the context state be recorded the latest?

The latest stage of the lifecycle at which the state of the context can be recorded in iOS is the applicationDidEnterBackground(_:) method in the application delegate (AppDelegate).

When the app goes into the background, this method is called, and here you can save the current state to restore it upon the next launch. This is important because after transitioning to the background, the app may be unloaded by the system.

Regarding view controllers, similarly, you can use the viewWillDisappear(_:) or viewDidDisappear(_:) methods, but for the global application state, applicationDidEnterBackground(_:) is the last reliable moment to save data.