Is the book "Mercurial: The Definitive Guide" up to date?

[Alberto Ridolfi]

Hello,

I am a Mercurial user with basic knowledge. I want to study Mercurial
deeper and eventually master it.

I'm thinking about studying the book "Mercurial: The Definitive Guide"
by Bryan O'Sullivan, but that book was published in June 2009. Since
almost 5 years have passed since the publishing of that book, and I
also have the impression that Mercurial changed a lot in those years,
do anyone knows if that book is a nice option for mastering Mercurial
and becoming an expert in it in 2014?

Thanks