Don't hold your breath.
@gambitmoth if you're referring to the development information on the official Xmoon forums, you should know that that post was made in September 2016.
The devs have been silent for almost two years regarding the new version, anytime they are asked the response is "We are still working on it" however with absolutely zero evidence to back that up, I am highly skeptical. They won't even mention what progress they've made or what they're working on now.
At this point I think it's safe to assume that version 4.0 is vaporware.