Flexi supports FlexCut in a way that you can assign FlexCut as a driver option to a cutcontour. So Flexi will activate FlexCut for this contour. FlexCut-Parameters have to be set at the plotter.
There are more enhanced support for example at Onyx where you are able to save multiple FlexCut-Setups in the software.
By the way: FlexCut do not need application support, you can set the plotter in FlexCut-mode, and it will apply FlexCut on every vector you send. But software support make it more functional (eg kiss-cut and FlexCut combined in one job) and more comfortable.