What happened to the Windows file? It's no longer available :(
Viewing post in Lust Doll Plus Save Updater comments
It was more work than it was worth, so it was discontinued. Instead, you can use the archives to update your save file using past versions: https://mega.nz/folder/M4U1mDrR#P8KOwqwwy9lQqG3fLRpcCw