Applies to:   

Windows Server 2012 R2     
Windows 8.1

Windows Server 2012 R2 RTM
Windows 8.1 RTM

Note:  You should check http://support.microsoft.com for the latest version of the different files.
Note 2:  These are not available in Windows Update.
Note 3:  You can download them without entering your e-mail address and captcha if you are a Microsoft Premier customer and have a http://Premier.Microsoft.com account.
Note 4:  Carefully review the list and decide which might be applicable to your unique environment.
Note 5:  Test in your test and your quality assurance environment.

Originally published Feb. 2014.   Updated Feb. 2014.

The list has been moved to the Technet Wiki below.

List of Hyper-V related hotfixes post RTM for Windows 8.1 RTM and Windows Server 2012 R2 RTM
http://social.technet.microsoft.com/wiki/contents/articles/30353.list-of-hyper-v-related-hotfixes-post-rtm-for-windows-8-1-rtm-and-windows-server-2012-r2-rtm.aspx

This should help with getting the list updated sooner with the help of the WW community.