ASAP: https://wyday.com/forum/t/3279/is-there-any-good-news-on-version-4-out-now/#post-16232
This is an unusual release (inlcuding lots of backend work that is the basis for a couple years worth of future developments). Subsequent releases won't be anywhere near this long between releases.
All that remains is a couple of bug fixes and finishing the documentation. No hard date. ASAP.