Same problem here. I was able to install 0.7 initially, but now itch only lets me "update" to 0.4. Going to library doesn't help - when clicking on 0.7 or 0.8 the version select defaults back to 0.4 and can't be changed.
I'm guessing in my case it has to with me buying the game for the price with the initial release discount, which is now below the mandatory amount (but that's just wild speculation).