Trying to pass custom Python goals to Kangaroo solver in Rhino 8

I’m trying to load some of my old custom kangaroo goals written in python, but the solver included in rhino 8 errors with “Solution exception:Unable to cast object of type ‘IronPython.NewTypes.KangarooSolver.GoalObject_2$2’ to type ‘KangarooSolver.IGoal’.“.

This worked fine in Rhino 6, haven’t tested 7.

Does anyone know how to work with the changes?