Vista extended support ends in April of 2017. It's the last holdout of Microsoft-supported mainstream versions of Windows (i.e., excluding fringe versions like Windows Embedded) that can't upgrade beyond IE9. Seems reasonable that the new version of Bootstrap (which you don't have to use--v3 still works fine) should not bother with support for a browser that will soon be no longer supported by the browser's own creator.
They should probably even consider dropping IE10 support if it is any sort of burden to them. IE10's marketshare is so tiny (smaller than IE9, IIRC). Windows Vista (i.e., "Windows 6") users used IE9 since MS didn't support anything beyond that for Vista while Windows 7 users mostly auto-updated to IE11.
They should probably even consider dropping IE10 support if it is any sort of burden to them. IE10's marketshare is so tiny (smaller than IE9, IIRC). Windows Vista (i.e., "Windows 6") users used IE9 since MS didn't support anything beyond that for Vista while Windows 7 users mostly auto-updated to IE11.