I’ve problems too with IE. A customer called yesterday about not being able to see the cart. I’ve now checked the site myself with IE 11.0.50 and I’ve the following problems (might be more but this is from a scanning):
cart doesn’t load; nor the top widget, nor the side bar widget… i.e. it’s not possible for the customer to check out.
the page doesn’t load correctly as the content is placed over the menu bar (page title or other other content in top of the page doesn’t matter).
Some content doesn’t load at all, e.g. grids
I’ve conversions from IE 11 in December, but after that nothing. So I guess it has to do with something in an upgrade from Januari.