So even jQuery is saying goodbye to hacks for old versions of Internet Explorer when jQuery 2.0 is released next year. Good riddance!
But for all of our legacy projects (and clients), this means we’ll being loading up separate old versions of the jQuery core for older versions of IE (jQuery 1.9 when 2.0 is released for every other modern browser).
I originally read about it here:
Loading a Different jQuery Version for IE6-8
See the jQuery core team’s follow-up here:
jQuery 1.9 and 2.0 TLDR Edition