if youre playing it on the pc version then you can try playing with the save folder open and copy the saves over to another folder.
ok then thats simple... maybe.
open the game to play it as normal, inside of the game's folder open www folder - open save folder - save game and while the game is still running copy the save file out of that folder.
a bit late to ask this, but what version of the game are you using? if this doesnt work might need to goto the patreon page to see if you can get in contact with the dev.
ok. the way i was able to get it to work is opening the save folder in the older version and copying everything over. you need the global.rpgsave from the older versions save folder. if its not in there then you wont be able to get the older saves to work. open up the hold version again and make a new save. that should get it back in there and allow you to copy it over to the new versions save folder along with your save files.