Will it still be evil and headbangingly frustrating and quirky like the others so far? When are they just going to get with the program, or will they ever? Personally, I hope they don't so that people abandon them for free software sooner, and that way I can use a shorter test:
var addEventListener = !-[1,] ? "attachEvent" : "addEventListener";
instead of testing for the methods themselves each time. Or will IE10 support both?