The most important part of this update is that adds support for Windows 8.1. It is not stated in the KB but I guess it adds support also to Windows Server 2012 R2 from client side of course. The full list:

Supported Platforms

This update adds support for Windows 8.1-based client computers in Microsoft System Center 2012 Configuration Manager Service Pack 1. Windows 8.1 is added to the supported platform list for the following features:

• Software distribution
• Software update management
• Compliance Settings

Issues that are fixed

Operating System Deployment

This cumulative update includes the following updates:

• 2869380

        (http://support.microsoft.com/kb/2869380/            )   

  FIX: A task sequence stops responding when multiple task sequences are started in System Center 2012 Configuration Manager

• 2870742

        (http://support.microsoft.com/kb/2870742/            )   

  FIX: An Alternate Content Provider does not work in a task sequence for a System Center 2012 Configuration Manager SP1 site

Additionally, this cumulative update fixes the following issues:

• The reimaging of an existing client computer may result in a policy being invalidated. This issue can occur if the SMS Agent Host service restarts before all Data Transfer Service (DTS) jobs are completely processed. Additionally, the PolicyAgent.log file on the reimaged client will contain entries that resemble the following:

  [CCM_Policy_Policy5.PolicyID="ScopeId_GUID/Application_GUID/CA",PolicySource="SMS:PRI",PolicyVersion="1.00"] is pointing to invalid DTS job [{DTS_JOB_GUID}]. Will attempt to re-download.

• Install Application Task sequences may take longer to complete if they are run from stand-alone media instead of a local distribution point. This issue can occur when multiple task sequences use large content files (for example, several hundred megabytes).

Windows PowerShell

This cumulative update fixes the following issue:

• The Add-CMDistributionPoint cmdlet incorrectly sets the value of the ServerRemoteName parameter to the name of the first installed site server. This issue could lead to clients accessing content on the site server instead of the intended distribution point server.

Software Distribution

This cumulative update fixes the following issues:

• Modern applications deployed to users of Windows 8 computers may fail if a non-administrator is logged on and has mapped a network drive. The AppDiscovery.log will contain entries that resemble the following:

  In-line script returned error output: Attempting to perform the InitializeDefaultDrives operation on the ‘FileSystem’ provider failed.

• A deployment created at a child primary site and then deleted from the central administration site may remain active on the child primary site.
• A pull-distribution point may crash when it tries to download packages. The PullDP.log stops recording any activity when this issue occurs.
• Packages migrated from Configuration Manager 2007 to 2012 Configuration Manager may not download to pull-distribution points unless the Update Distribution Points wizard is used. Error messages that resemble the following are logged in the PullDP.log file:

  CPullDPPkgJob::LoadJobFromXML() could not load any content jobs from XML!
  CPullDPPkgJob::LoadJobFromXML() could not fully load job! Malformed or incomplete XML. Job has failed.

Windows Intune

This cumulative update fixes the following issues:

• An ampersand (&) character in the Company Namefield of the properties of the Windows Intune subscription page prevents the creation of policy files. Additionally, error messages that resemble the following are logged in the Policypv.log file:

  XML Parsing: line 2, character 315, illegal name character

• The TEMPDB folder for a site database may grow quickly after "Windows Intune Subscription and Connector" is enabled.

Endpoint Protection

This cumulative update includes the following update:

• 2865173

        (http://support.microsoft.com/kb/2865173/            )   

  An anti-malware platform update for Endpoint Protection clients is available from Microsoft Support

Site Systems

This cumulative update includes the following update:

• 2867422

        (http://support.microsoft.com/kb/2867422/            )   

  FIX: Errors when you try to install or recover a secondary site in System Center 2012 Configuration Manager

Additionally, this cumulative update fixes the following issue:

• An update to the MCS.msi file does not upgrade the Multicast Configuration for Distribution Points. See the System Center Configuration Manager Team blog for more information about this known issue

        (http://blogs.technet.com/b/configmgrteam/archive/2013/08/07/known-issue-update-to-mcs-msi-fails-to-upgrade-the-multicast-configuration.aspx)   

  .

Reporting

This cumulative update fixes the following issues:

• Reports are not displayed when a user does not have EXECUTE permission on the fnGetSiteNumberobject. When this issue occurs, you receive errors that resemble the following:

  An error has occurred during report processing. (rsProcessingAborted)
  Query execution failed for dataset ‘FirstMatchingAppOrCollection’. (rsErrorExecutingCommand)
  The EXECUTE permission was denied on the object ‘fnGetSiteNumber’, database ‘database_name‘, schema ‘dbo’.

• Computer Activity Data is missing from Power Management reports for Windows 8 and Windows 8.1 clients.

Software Updates

This cumulative update fixes the following issue:

• Software Updates for Windows XP and Windows Server 2003 may have the Downloaded value incorrectly set to No on child primary sites, although the value is set correctly to Yes on the central administration site. This issue occurs because of a replication timing issue.

The update can be downloaded from here.