I wasn't able to save manually with new version too. Autosaves worked tho and if that's the case for you i might have the help you need.
1. go to your LocalLow folder in appdata and move your Sandlust Games Ltd folder to a different location.
2. start game now, newgame let it create a new folder in your locallow
3. close game and copy/move your backup into the newly created locallow Sandlust Games Ltd folder - don't let it overwrite anything
After these steps i was able to load my old savefiles and make new ones.
#edit: kinda same solution as previously mentioned