Looks fantastic, but I can't use it in my projects because it only seems to support very recent versions of IE (9+), Android (4.3+) and iOS/Safari (7+). I don't

Looks fantastic, but I can't use it in my projects because it only seems to support very recent versions of IE (9+), Android (4.3+) and iOS/Safari (7+). I don't care about IE, but I do need to support Android phones from 2012. Is there really no way to write a modern rich text editor that remains compatible (and/or degrades gracefully) with slightly older browsers?