Editor issues after 5.4 on IE

One of my editors uses IE, and for him the editor causes issues after the update to 5.4, in particular he was unable to use the media button for uploads and the switching between text and visual editor (we use the classic editor) didnt work either. The problem does not exist on other browsers. Emptying all kinds of caches (Breeze plugin, browser cache, memcached, varnish) does not help. Just wanted to flag this. If course IE is always an issue but maybe it is something that could be looked into for downward compatibility issues….