To quote the jQuery folks: 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 [...]
jQuery 2.0 to drop IE 6/7/8 Support is a post from: Sean Walther's Blog
