> Some glorious day in the future, jQuery 2.0 will be the only version you’ll need; until then we’ll continue to maintain jQuery 1.9 The benefit is that if you

> Some glorious day in the future, jQuery 2.0 will be the only version you’ll need; until then we’ll continue to maintain jQuery 1.9 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.