I asked someone in a f2p clan and they said in 5 days. I can't guaruntee this is correct, perhaps something to go by. Don't take my word for it, i'm simply rumouring.
I asked a mod who said it was coming out sometime in May, then 2 weeks ago(ish), a mod said 3 weeks or so, so probably sometime within the next week. Then again, this is Jagex we're talking about so you never really know when, lol.