You have to redownload it, and you can carry over your save if you copy your save folder to the new one and it's all done
Ah, yeah back when I tried to switch from 0.37 to 0.38 I looked up how to carry over savefiles, and I found couple of comments where you had to copy and paste it...
When I tried to do it without copy pasting it didn't work, so yeah I've been doing it like this just to be sure.. It's not complicated at all so I don't mind doing it everytime.