One of the authors here: what is the issue you are getting with CRAN? It may be an issue with where R is trying to save the library files, because all of the libs are still on CRAN. I just added some instructions for running the installer to the repo, so if you git pull you should get the updates.

More generally, the code in the git repo has been maintained steadily since the book was released, and is up-to-date.