private void OnAppUpdateOptional(VersionEventArgs e)
 {
     if (AppUpdatedOptional != null)
         AppUpdatedOptional (this, e);
 }
 private void OnAppUpdateNeeded(VersionEventArgs e)
 {
     if (AppUpdatedNeeded != null)
         AppUpdatedNeeded (this, e);
     IsDownloading = false;
 }