Obviously i cant speak 4 d1, i'm just another user same as you, but that question to me sounds like a how longs a piece of string situation.
Hes doing a fantastic job, taking suggestions on board and due to that his to do list is getting as much stuff added to it as taken off (see various threads all over the board).
If he decides thats that we're stable too soon then we will miss out on a lot of great features, and of course upgrades are not obligatory, just check changes log and see if you need it
