IE11 has an IE7 compatibility mode so line-of-business apps are going to be targeting IE7 for a long time to come. One of my employer's clients is only now willing to pay to upgrade from IE5.5 rendering on IE8 to IE7 on 11.
I was involved in a similar discussion and the logic was hilarious. "Browser standards change too often." (!?) "So we're only to support an old buggy implementation of the specs that is sorta emulated in one modern browser." They sounded like they were afraid of having their security blanket ripped away.
If you still have some IE5 stuff, my guess is that you have to bring it up to the HTML5 table layout zone. And then you need to back polyfill a bunch of stuff to deal with the "IE7 mode" requirement.
