All save files are stored on your computer in a separate folder, and uninstalling the game doesn't delete them, so after installing a new version, all old saves will be as accessible as before.
However, it's not recommended to continue playing with old saves on new versions with major updates, as the game may become unusable. New items needed for progression may not appear in old saves; objects may appear in textures; building elements may overlap with older models. The list of problems is long.