I don't believe the rumors that they are making it thinner. I imagine those will be coming next year.
I would be willing to bet, though, that if they do make it thinner, they will design it in such a way that the old cover will no longer work. At the very least they will move the magnets around or switch the polarities in such a way that it will no longer work. Those covers are incredibly high-margin and they want to sell as many as they can.