It's nice of you to want to support the creator but you could do that voluntarily. The creator "selling" the game to me without me actually having it is a little less nice.
I believed I had bought this game and I saw no warning that this wouldn't apply to later versions. As another comment further up states, itch.io strongly recommends creators don't do this.
The creator specifically stated in an earlier post that this wouldn't happen. Apparently he lied.
I would even be ok with it if I could at least top off my purchase, but basically I have to write it off completely, to "support" someone who doesn't even deem it necessary to say something about this situation.