http://blogs.technet.com/b/dynamicspts/archive/2013/02/18/crm-sdk-update-v5-0-13-available-now-for-polaris-and-ur12.aspxWe can download the latest SDK for Microsoft CRM 2011, which contains the updates for Polaris and Update Rollup 12 from the link below. Microsoft Dynamics CRM 2011 Software Development Kit (SDK) You can also view it online from the link below. en-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)