1.6? I unfortunately don't have a time machine to know what would be in a potential future v1.6 update, and because of it, whether it would be possible to make a save from that future build compatible with the current v1.55 build. I do hope that future update was a banger, traveler!
Any save from an update prior to v1.0 is incompatible with the current builds, as it would simply break the game.