I understand why they'd drop IE8 support in 2.0 but it's still a bitter pill to swallow.
http://blog.jquery.com/2012/06/28/jquery-core-version-1-9-an... "Our goal is for 1.9 and 2.0 to be interchangeable as far as the API set they support. When 2.0 comes out, your decision on which version to choose should be as simple as this: If you need IE 6/7/8 support, choose 1.9; otherwise you can use either 1.9 or 2.0. ... If your web site needs oldIE support, and we expect most sites will need it for at least another year or two, you can use IE conditional comments to include version 1.9 only when visitors are using oldIE:"
The benefit is that if you're targeting mobile only, you can use the optimized 2.0. For other use case there's still going to be 1.9.