The new features are:  
 
TreeView nodes
The TreeViewNode class represents nodes that can display hierarchical data. The root items displayed in the node can be accessed through the RootItems property. New items can be added to and removed from the returned collection. The root items can have child items on their own and so on. For more information, refer to the TreeViewItem class.
 
Flowchart graph layout
FlowchartLayout recognizes program code -like patterns in the graph, such as loops, sequences and if/switch branchings, and arranges them recursively. FlowchartLayout could be used to arrange other types of graphs as well, though with some restrictions. For example it treats all back links as loops in the code, and expects that they are nested - loop links starting closer to the stop node should end closer to the start node. Another similar restriction is that there shouldn't be any cross-links that connect different branches of a decision sub-graph.
 
Topological graph layout
If the underlying graph if acyclic, TopologicalLayout arranges the nodes linearly in such a way that each node comes before all destination nodes of its outgoing links. The links are drawn as curves above the chain of nodes, with their height proportional to the distance between the nodes. If the graph is not acyclic, the layout algorithm finds an ordering with a minimal number of back links, and draws the back links below the chain of nodes.
 
Link routing enhancements
A much faster link routing algorithm has been implemented. It can arrange a thousand links for just a few seconds, while older versions would require several minutes. Now it is also possible to create custom routing classes to be used when a link must be routed by implementing the ILinkRouter interface. An instance of such class can be set through the LinkRouter property of the Diagram. NetDiagram provides two classes that implement ILinkRouter - GridRouter and QuickRouter. By default LinkRouter is set to a QuickRouter instance.
 
Adjustment handles styling
The ActiveItemHandlesColor, SelectedItemHandlesColor and DisabledHandlesColor properties have been replaced by ActiveItemHandlesStyle, SelectedItemHandlesStyle and DisabledHandlesStyle. The HandlesVisualStyle objects returned by them provide sub-properties for greater control over the appearance of selection handles. The adjustment handles can now be painted not only in solid color but with arbitrary brushes, such as LinearGradientBrush and TextureBrush objects.
 
Miscellaneous
 - The JavaArguments property lets you specify runtime arguments for the Java plug-in, such as the amount of memory allocated.
 - The Focusable property can be used in ImageMap mode to prevent the control from getting the keyboard focus when clicked.
 - The ShowLabels property specifies whether the ShapeListBox control should render shape labels.
 - The createColor method of ScriptHelper creates a Color instance.
 - Use the createPaper and createPageFormat methods of ScriptHelper to create objects required for print job setup.
 - createSize and createSizeF methods of ScriptHelper create Dimension and Dimension2D instances.
 - DiagramApplet provides local clipboard support to avoid security warnings.
 - Client side events are now raised in Silverlight mode.
 - ShapeFilter can be used in JavaApplet mode.