EDIT: Aaahhh!! the new version is Windows/OSX only. Same deal with FreeCiv go figure, I will have to just make due with the older versions, still like new to me anyways. I am fairly new to linux as a whole, having just brief experience in the past, so maybe there is something I am missing.
Unless you compile it yourself:http://www.freeorion.org/index.php/Compile
I really would recommend .3.17 or later if you can figure out the compiling, since we have been focusing on playability and fun recently.