You just would need to download and extract the new version and run; provided your save from the last version is before the credit roll from the prior version, you should just be able to load it up and go from there. The only time you will need to delete and re-install anything is if you have mods installed, and even then most of the modders for Eternium work in tandem to the creators and have the new versions ready for the public release, so you can just download the new mod file and re-add it with out much worry