Since 1.4 it is possible there is the annotation @DrawSequenceDiagram available for the generation of sequence diagrams. But you need the plot-utils tools with 'pic2plot' to convert the *.pic file into a Postscript or SVG file.
Because not all developers have the pic2plot command on their computer it would be helpful if the format of https://www.websequencediagrams.com/ is also supported.
will be supported with 1.6
supported with 1.6.0