brinked - 6:36 pm on Sep 7, 2012 (gmt 0)
It is just as you said. Its currently brewing and it is not completely rolled out yet. I do not think google has ever announced any update while it was not completely rolled out.
Announcing something that has not settled yet would not make a lot of sense. I am sure they will give you word when it is 100% rolled out across all data centers and they feel comfortable with the results.
If they announce it prematurely, and then they see something that needs to be fixed, wont make them look very good.