-One of the most popular libraries is dropping support for IE 6,7, and 8. Thus, yet another cornerstone of the web is going to push users forward and increase the chance that those miserable browsers will disappear.
The most disturbing thing I find is that there are developers that are DEFENDING existence for those older browsers. Are you masochists? Do you enjoy the headaches of fucking around with those??
"Oh but so many clients are still using them, and it writes off potential users!"
How can we ever expect for them to upgrade their damn browser unless the builders the web (developers, not just browsers) quit allowing them to rot in complacency????
Of course, there is a thing as going "too leading edge" and expecting "too much" from the user...but when the cornerstones (libs, browsers, etc) start pushing them forward - then we should embrace this change. Coding for the multi-browser/platform/device/version web is hard enough.