They are working on an updated version as I write this. From what I remember, the only things that are now incorrect in the current book is the number of electoral districts (308 in the book, now 338) and the lyric change of O Canada from "True patriot love in all thy sons command" to "in all of us command."
My wife used the current book to study and she wrote and passed her test on February 4. The only changes I made her aware of are above, because, again, those are the only changes I am aware of. Study from the current book and you'll be fine. Just note the two changes.
Jim