With Microsoft making big gains to support MVVM in the Portable Class Libraries, will Prism 4.5 be designed to take advantage of this?
 
For example, when creating a view-model class you'd extend from the NotificationObject abstract class. But, unless the NotificationObject class is in its own Portable Class Library then this would be impossible (you can't reference a standard .NET class library).
 
I guess I'm just asking which, if any, classes will be moved into a Portable Class Library instead of a standard .Net 4.5 class library. My suggestion would be to move as much as we can into a Portable Class Library.