The road map they laid out on Patreon would put it earliest in the next 5-6 months. But I suspect there is going to be a delay of some sort, whether it's Anduo adding more content than originally envisioned, or wanting to take a little more time to polish. I would imagine that it shouldn't be longer than 10 months, but don't take my speculation as gospel.
Additionally they have been adding content to an earlier game of theirs called Rosas are Red. I reached out to them about that game, and they let me know that the only version that has been released is the original release from 5 years ago, but they plan on releasing that at some point as well.