Created to simplify the process of writing JavaScript and manipulating HTML, jQuery began life a mere seven years ago, but quickly found favor with developers sick of dealing with cross-browser JavaScript hassles. According to one survey published last year, jQuery turns up on roughly half of all sites on the web.
Will dropping support for older versions of IE change that? Probably not. If your site needs to maintain support for IE 8 and below (or even IE 9 and 10 running in compatibility mode) you’ll just need to stick with jQuery 1.9 or below.
“jQuery 2.0 is intended for the modern web,” writes jQuery’s Dave Methvin on the Query Foundation website. “We’ve got jQuery 1.x to handle older browsers and fully expect to support it for several more years.”
If you want the best of both worlds you can use a conditional comment to serve 2.0 to newer browsers and 1.9 to older ones, but the far easier way to go is sticking with jQuery 1.x. For now at least the primary use case for the 2.0 line is situations where IE support isn’t a consideration — think Chrome or Firefox add-ons, PhoneGap apps or node.js.
Source: http://www.webmonkey.com/2013/04/webs-most-popular-javascript-library-drops-support-for-older-versions-of-ie/
