I would like to clarify that the patch will not install and this is expected behavior since when you are running your application on Windows 8.1, it is supposed to have .NET 4.5 installed and this patch is for .NET 4.0.
I notice that after applying the suggested sample code for determining your user agent it returns a bit different result than the expected. A possible reason for this issue could be that your user agent string is not found in the browser list. In the following post
one of our customers suggests a way to match your user agent as IE11.
Please let us know how that worked.
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