I'm the author of the Play book. On the subject of that book... There are only two significant things that are out of date. A minor tweak in the JSON library a

I'm the author of the Play book. On the subject of that book... There are only two significant things that are out of date. A minor tweak in the JSON library and the new DI system. The former is an easy fix. The latter will require a new chapter. I'm happy to chat to anyone who is interested in collaborating on these parts.