Non-blocking layout methods - All graph layout classes now contain an async ArrangeAsync method that runs layout calculations in the background.
VirtualizingDiagram improvements - VirtualizingDiagram can now contain different type of nodes
Overview improvements
The boolean FitAll has been replaced by the ScaleMode enumeration property. It implements a third scaling mode where an overview's scale stays fixed and ignores a diagram's zoom level.
If AllowZoom is enabled, users can zoom the diagram by resizing the overview's viewport tracking rectangle.
Miscellaneous
The LinkTextEdited event is now raised when a LinkLabel has been edited. The edited label is specified via Label property of the event arguments object.
LinksPadding property added to LayeredLayout specifies how much space to leave between links when LinkType is set to Cascading.
GridAlignPoint property of DiagramNode class specifies which point of a node should snap to a point of the alignment grid.