Official word on Oni's patreon is the next number is 1.0:
Ok, so with any luck, version 0.999 is done, and if you're good with math, you'll have realized that we have something a bit special coming up. . . an entirely new decimal place!
Ok, kidding, yes, the next version to be released, likely in a couple months, will be version 1.0. Probably. I'm kinda thinking that since my first releases are a buggy mess and take about 5-8 builds to become reasonably stable, I should actually release the version as 0.999m or something and iterate through the letters until we get stable, and then release it as 1.0, but 1.0 is at least coming now.
And so the goal with it will be "polish," I want to go through and update elements that have been in there since early versions, tidy up things that need it, make sure that everything is stable and consistent and worthy of a "complete package." I'll be asking you guys for things you think need tweaking, and maybe running some polls over the next months so to which direction I should take a given update. I've already been working on some of this stuff for a while now.
So that's it then, we're done with the game? Of course not. I intend to continue adding new characters and new scenes and other new content to the game into 1.1, 1.2, 1.201, and beyond. At least so long as you guys still seem interested in the project. We'll be doing a new character poll next month, and that character would be intended to start in version 1.1.