It&#x27;s not as if web developers like supporting broken, outdated browsers.  It&#x27;s done because without the users using those browsers, the business would be worse off.<p>There are lots of intermediate steps like warning about an inferior experience, but at this point it&#x27;s necessary to test most websites on at least a few versions of IE9.<p>I&#x27;ve found that using react I&#x27;ve had very easy compatibility with older IE, etc. The only thing I&#x27;ve had to do is install a polyfill or two.