In the main 2kki folder (the outdated version) there should be an .lsd file for each save file, such as "Save01.lsd" for file 1, "Save02.lsd" for file 2, etc. Just copy and paste those files into the main 2kki folder of the new version of 2kki. When you launch the new version, it will load your save files (I think when choosing the second main menu option, continue).