Removed IE support code in 4.1.x:
- polyfills for HTML5 elements and attributes
- polyfill for Array.prototype.indexOf at vw_Hard_Core._indexOf
- the CSS structure "@supports (display: flex) { ... }" which triggered a bug on CloudFlare systems (unclear whether CloudFlare fixed the issue yet as of this writing). In 4.1, all flex code is in the main CSS.