My download from steam is claiming its only 1.3

, how much does 1.5 cost?
*Edit: OK, so v1.5 is the U-Boat Expansion? If I have already purchased and downloaded the base game through Steam and wish to get v1.5, what is the best way to proceed? Or is v1.4 just v1.5 without the expansion? I plan on getting the expansion anyways but I am a little confused... Maybe just picking up a physical copy of gold would be best anyways (since they are the same price), time to do some research...