Last friday, Microsoft released CU3 for System Center 2012 Configuration Manager SP1. Most important Point for me with this CU is the Support of the following Features for Windows 8.1:
•Software distribution
•Software update management
•Compliance Settings
Even the official TechNet site (http://technet.microsoft.com/en-us/library/gg682077.aspx#BKMK_SupConfigClientOS) does actually not list Windows 8.1 as supported for SCCM 2012 SP1, Server 2012 R2 is also missing, and in the Statement for this CU3 (http://support.microsoft.com/kb/2882125/en-us) only for Windows 8.1 is a note. On other Websites you can read, that Widows Server 2012 R2 is supported too, and I would agree with that, but I’m not sure.
Although if we would like to make Operating System Deployment for Windows 8.1, we still have to wait for the R2 release.

Finally the download link for SCCM 2012 SP1 CU3:
http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=2882125&kbln=en-us

And the KB Release Articel again (KB2882125):
http://support.microsoft.com/kb/2882125/en-us

Martin