FFox asks me to update but at cost of disabling Nuance PDF Converter, no can do, need that how update and prevent. Thanks

FFox advises me of needed update. I start the update, but it tells me that Nuance PDF Converter is incompatible, and it will be disabled, until further notice. I need that program working, and cannot allow it to be disabled until some unknown future date. How can I update without disabling the program? Thanks Kiko Sarasua