Version 0.13.3 is the latest version. Just downloading and playing it is all you have to do. I can’t imagine how that would give you an old version.
Save files and mods will not be affected, though you can use the “save to disk” feature to be extra safe. Saves and mods should automatically transfer between versions. Just run the new version and everything should be there. You may want to re-download the game as I’ve just released a patch only a day or two ago.