When I started work on the second edition Clojure 1.7 was still beta (not yet even release-candidate); Clojure 1.8 was released less than a month after the book went to print.
The first Clojure version I knew was 1.4 or 1.5, so I have no first-hand experience of the tooling and library upheavals in 1.3. From what I hear, lot less has changed between Clojure 1.6 and 1.8 than between 1.2 and 1.3. I myself still actively develop on projects that use Clojure 1.6, although they will probably be upgraded soon since the upgrade is relatively painless.
The fundamentals of Clojure and Clojure's FP style is unchanged between 1.6 and 1.8, so I still think this book is a solid introduction to Clojure for someone who has no Clojure or FP experience. It's not a great book for someone who has some Clojure experience and is looking for more. For that I recommend The Joy of Clojure
, now in a second edition, but alas also updated for Clojure 1.6, not 1.7 or 1.8.
Clojure 1.7 added transducers and reader conditionals; Clojure 1.8 added the socket server, direct linking, and some more clojure.string functions to ease interop. Of these, the only feature I sincerely regret not being able to devote a chapter to is transducers (and reducers, a closely-related 1.6 feature I also don't talk about but which I would have liked to). Transducers add a new 1-arity to most of the core sequence-processing functions which I'm sure a beginner will accidentally stumble into and be very puzzled by. Also, transducers+reducers (and the IReduce protocol) are part of what makes Clojure special. I'm also not sure if there is a Clojure intro book currently in print which talks about transducers, so it also would have been nice to be first-to-print with that.