You dont KNOW it is moving out because theres not anybody outside WotC who KNOWS it is moving out.
There is a general expectation that there will be a December 1st announcement removing Ice Age, Alliances, Homelands, 5th Edition, and Dual lands from extended, which would be legal in competition on Jan 1st.
This is only a widely spread rumour, but its one I personally think is 90%+ likely to come true.
There might be a concurrent rewriting of the T1.5 format to make it more of a halfway house between 1.x and T1 for people who want to use their Duals still, losing many of the older cards from the format, possibly to make it 4th Ed + all the expansions with bans/restricts as before.