This release mostly concerns the comments system, which has been completely rewritten. It should function about the same though. The comments now include a tagging system to help moderators better organize all the comments posted to docs.sencha.com.
The only other new feature is the ability to specify a path for each guide in guides JSON config file.
But there's a bunch of bug fixes. See the changelog for details. So you should still upgrade
In other news I've simplified the initial setup procedure of JSDuck development environment. See the Hacking guide if you want to jump in.