I'd be surprised if you get the second-last DVD (the 2013 edition was released in 2012) still in shops, and outside Germany. However, as far as I recall, you need nothing to install from it, since you already have it installed (polus updates and new reserves), and I think back then they said that the code in the box unlocks additional equipment that you then have no longer to buy separately, it also adds 6 months of membership. But one needed to enter the code at a different site.
Best advise would be to check in their forum for "DVD 2013 Deutsche Wälder". I do not recall the details precisely anymore.
The latest DVD special edition is "2014", it also adds some stuff to the membership of 6 months, and a Blaser rifle, but the content list is much more limited than it was with the 2013 edition.
Today we're hunting T-Rex.