The most recent official comments I' ve seen were from early Jan of 2020, where Juan mentioned targeting a release of 4.0 by mid-2020. For reference, that's mentioned at least here:
https://www.phoronix.com/scan.php?page=news_item&px=Godot-4.0-NYE-Look
Obviously though, we're past that particular mark now. While I haven't seen any more official estimates (maybe they exist?), I'd say the real answer is likely to be:
It'll be released when it's ready