We just finished our book on Advanced Swift, and I think you folks are the perfect crowd. There's also an online preview =). Let me know if you have any questions!
Are you planning to release some updates sections for Swift 3?
Presumably this is because VAT is charged on ebooks but not on physical books.
I'm starting to do programmatic layouts in code for my side projects and I think there are huge advantages to building user interfaces in code, but everyone seems to just do storyboards. Instead of waiting for Apple to release nice abstractions like UIStackView, in code you can create your own layout abstractions the way you'd like. There seems to be close to no content based around this unfortunately.