CurrentDomainException - GRBL Polargraph

[Bass3d]

Hi there,
IOSender works beautifully with my Arduino - GRBL DIY laser-plotter.
Today I connected IOSender to my new DIY Polargraph that uses a GRBL 0.9 Fork with Arduino and it crashed.
I tried all 3 versions available, with the same result.
Normally there's no problem driving it with other software like UGS, GRBL Plotter and so on.
When I lauch IOSender after a couple of seconds it crashes: with the error CurrentDomainException - unhandled exception- String format not correct.
Maybe there's something with the added $28 and $29 GRBL Polar parameters that aren't handled.
Those two parameters are respectively the distance from the two steppers ($28) and the distance of the pen from the ideal line connecting the two steppers ($29) . These two numbers are handled as "Unknown parameter" by the other programs.
Thank you for your effort.
Stefano

[terjeio]

The GRBL 0.9 message format is not supported, please update to 1.1.