Hello, a new version will be up soon (~2 weeks), no worries. This isn't a paid demo, when you bought the game there, it was an early access game here (it had warning very visible about it)). I had to change it to a demo because of problems with itch.io with adult content.
It can't be since 287 days you received a game update, 13.5 is much more recent than that.
Thank you for understanding.