New CRM 2013 SDK could be downloaded from the following link http://www.microsoft.com/en-us/download/details.aspx?id=40321 This download inludes UII as well. "User Interface Integration (UII) solution framework, which includes a deployment guide, development guide and api reference. UII uses Microsoft Dynamics CRM for the delivery of configuration data for the Integrated Agent Desktop. It includes development and run-time components. Applications built with UII can provide unified access to customer information across different systems and can aggregate different modes of customer interactions or channels." (REF: Microsoft CRM 2013 SDK Download).