At MIX11, I am releasing a new preview of MVVM Light version 4. This new preview contains one small change and one large change. ObservableObject replaces NotifyPropertyChanged In the previous preview, I introduced a new class named NotifyPropertyChanged. However, I got a few suggestions to rename this class to ObservableObject, which is indeed a better name. In BL16, NotifyPropertyChanged was deleted and replaced by ObservableObject. Nothing else changes, just the name. ObservableObject is a very ......