The default app has not been configured yet

Question

I\'m trying to upgrade my app to the new version of Firebase. I went through the setup guide and edited all of my code to match the new syntax. However, when I run the app,

Answer 1

In AppDelegate.m, outside of didFinishLaunchingWithOptions,

override init() {
   FIRApp.configure()
   FIRDatabase.database().persistenceEnabled = true
}