To locate and backup your saves, read the information
here which tells you how to find your ufoconsole.log. In that same folder you'll see a directory with save files. Simply copy those to back them up. Uninstalling the old version and installing the new shouldn't overwrite the saves, but it's always good to backup.
Next to the full installer on the download page there is a link to just the binaries. This will cover changes to the source code, but not the full data -- sometimes it works to just update the binaries but sometimes changes in the source code require changes in the data, so it probably wouldn't work to go from March to today with just binaries.
The best thing in your situation if you plan on regularly updating is to follow the steps to checkout our
git repository and compile yourself. But this does require a certain amount of technical knowledge and a ~6gb download up front, so it depends on how determined you are.
