It is unclear currently as to how this will work for the consoles. Most likely you will need to start a new save, though there have been hints of having options for 1.4 and 2.x both available.
Q: Save incompatibility between console versions? Also, will there still be Save incompatibility between patches? A: Due to the technical architecture of 7 Days to Die’s game engine, users will have to start a new game with each major update. Eventually, this will not be the case.