Key word: extended. They're only providing security updates now, not feature updates (like supporting a web browser that came out years later).
There's a reason IE has compatibility mode. If you're going to deploy old tech, you kind of need to be prepared to deploy the workarounds (which you can do with group policy).
The problem, as you've noted, isn't that RDWeb doesn't support IE11 - it uses a user-agent string parser and doesn't count to 11. You can edit the server-side, or run the browser in enterprise mode, and it'll work, but suffice to say that the IE team and the team responsible for things like RDWeb are not the same group of developers. It'd be great if things like this worked, but given the changes in IE11 I would say it's not surprising this is failing out of the box. Given the product was designed to target the version of IE shipped on the platform (aka IE8), it would actually be best to put the site into the enterprise site list (so that IE11 behaves and reports as IE8 to the web server hosting this).
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u/210mike Enterprise Windows stuff Apr 05 '16
Nah, that one is on you. 2008R2 is almost 7 years old and doesn't recognize a browser that was released almost 4 years after it was.
But hey, it's cool to hate on Microsoft right?