Internet Explorer 8 Addons to work in IE11 Enterprise Mode ?

As my subject is, will old IE8 addons (that didn't work in IE9-10) work in IE11 with Enterprise Mode?

We have a supplier who req an addon to be installed in IE to be able to use their webportal.
Sadly this crappy addon hasnt beeen updated since IE8.
They promised an update later this year that should work with newer versions of IE, but when and how we dont know.

Of course you cant tell me if it will work with this specific webportal and addon, but I was thinking if IE11 would support old addons in general?

Thanks :)