You need to look in Help > About DAZ Studio, and that will tell you what version you are running. If it is 4.0.x.x, then you will need to download the latest version. If you reset your download from your Itemized Order Hiistory, you should get 18.104.22.168 which will work for you. It has a seperate installer for the content called Gensisi Starter Essentials which must be installed as well. It updates Genesis to the latest .DUF file format, and loads the rest of the content as well.
There is a newer version available in the store, 22.214.171.124, which fixes some issues that 126.96.36.199, but it is still classed as a Beta (Iuse it with no problems so far though) It is really up to you which one you install, either will load Mavka for you.
The Beta version fixes a problem with Uberarea lights, so if you use them, then you should really get it. Hope that all makes sense?