Brad Adams gives us a non-official preview of what classes/members will be obsolete when Whidbey comes along. It's good to know these things as soon as possible so you can start moving your code away from them now instead of doing more work in the future. One thing he notes is that “Just to be clear, these members are still in Whidbey, applications built against them will continue to work, but when you recompile you will be asked to move to the updated version.”