I paid for 0.3 when it came out and 0.4 now, I don't think there's an option to upgrade. Why not purchase it again? Devs need support
Updates aren't upgrades. If it was a new premium or continuous backer exclusive then yeah that's an upgrade. But the way it was phrased (and the way it's commonly done) is that purchasing a game also gets you the updates.
looks like new version is now available for us who bought the .3
Thanks man!