Simple. The things they are updating are content additions not basic game engine changes. They are content and enabling things that have been in place since 2011. Most of the new race is already there for years - just never activated. I know because I have already seen inside the new town a year ago (Go to Rembeck and you can see the outside of that town).
I even have some screenies of it, but I won't post them because it would not be fair to PlayWith to post spoilers of their 'surprise'.