IBM plans to protect customers' past investments in IBM integration software, and does not expect current customers to migrate immediately from currently entitled products to the new WebSphere® Process Server and WebSphere Integration Developer offerings. To facilitate the extended migration period some customers may require to move to WebSphere Process Server and WebSphere Integration Developer (and to avoid "double payment" during that migration period), IBM is offering customers complimentary "extended entitlement" to WebSphere Process Server and WebSphere Integration Developer until they fully migrate to WebSphere Process Server and WebSphere Integration Developer.
Additional links:
WICS migration Redbook (link resides outside of ibm.com)