2 stars. I didn't mind the fact information is outdated, I can pretty understand why. However, I expected the author could go deeper in concept explanations, specially about redux. Instead, he started spreading a pile of code with some strange solutions that probably could be better designed, specially if it had automated tests in mind. By the way, he doesn't even mention automated tests. I probably set too high expectations beforehand due to the "Mastering" part of its title.