It seems to me the out of stock stuff has the slash through the color or size. So when the color disappeared completely despite the guy wearing the solid grey in the picture, I made the discontinued hypothesis.
I assume they don't want to advertise it as being discontinued until they are ready, because they want to maximize the remaining stock and some people will be more likely to hold out for the new version otherwise. Or if they roll it to the Outlet before the new version is ready, you'll have a bunch or people asking why they're no longer making it.