A cool thing about a lot of the agency work I did early in my career is our audience was not actually the stated audience, it was the staff at the company that hired us. And one of the companies was on IE7. So yeah, I've nine-sliced a gif or two and done a few clearfixes in my time, haha. Never ran into a lot of these, but these weren't apps so much as brochures that happened to be online. Luckily enough we could control the environment pretty well to avoid actually needing noConflict() on jQuery.

But that was in 2011–'13 and things have gotten a bit easier since then and it's up to us to stay abreast of what's possible on the platform.