We are starting beta tests of Flowchart.NET 5.3.4. The new features are: 

Support for custom arrowheads
The type of the HeadShape, BaseShape and IntermediateShape properties of DiagramLink has been changed from enum ArrowHead to class Shape, which is also used to define ShapeNode shapes. The ArrowHeads class now exposes Shape definitions that correspond to the ArrowHead enumeration members from previous versions. It is also possible to assign any Shapes member or a custom shape as an arrowhead. When used for arrowheads, position (50, 0) in the shape definition corresponds to the arrowhead's tip point.

Additional arrowhead enhancements
~ Now IntermediateShape arrowheads are also rendered for Bezier links.
~ Different arrowhead shapes can be filled with distinct brushes as set through HeadBrush, BaseBrush and IntermediateBrush.
~ Arrowheads can be custom drawn at arbitrary locations through the DrawArrowhead method.
~ Support for intermediate arrowheads added to DxfExporter.

Miscellaneous
~ The ShapeDesigner tool now supports filled decoration objects (used in BPMN shapes).
~ ShapeDesigner allows drawing the shape's text region outside the shape outline.
~ HitTest method added to TreeViewNode.
~ A new LoadFromXml overloaded method allows loading diagram items without changing the diagram's properties.
~ UBendMaxLen property added to QuickRouter.
~ SvgNodes support rgb(%) notation for color values.
~ Added support for SVG symbol references.

If anyone is interested in trying the beta, please download this archive, which includes updated assemblies, help file and ShapeDesigner executable:
https://mindfusion.eu/_beta/Diagramming.WinForms.534.zip