Many businesses rely on Microsoft Silverlight to run their business and consumer applications. Until recently, Microsoft did not have a clear support policy for Silverlight. Now we have it.
Although Silverlight is not a tool, its support policy is similar to the tools category where Microsoft provides a minimum of 12 months notification prior to the end of support.
Silverlight is unique compared to other Microsoft run-time products in the sense that it is serviced through either GDR releases (a minor update to the runtime) or new version releases (so new releases not only add functionality, but also fix issues in previous versions).
Silverlight does not support side-by-side installation (so users can’t run two versions of Silverlight on the same computer at the same time), however since new Silverlight releases are fully compatible with previous versions, existing applications should keep running with no change.
For more information, read the full details of the support policy here.