Iām totally new to CoreData and I want to learn it. But in swift 3 there are quite some changes to CoreData, I think (this persistent container, for instance). Is it worth it reading the book now? Or are there too many things that change the fundamentals of CoreData?
The fundamentals what you would learn are still there. I would definitely get started on it. NSManagedObjects, NSFetchedResultsController, Entities, Attributes and Relationships, Fetches, NSManagedObjectContext are still the same and that is a lot of material to cover in itself. I would definitely get a jump on it.