CRJ, DC-6, A32NX?
This is kind of an overstatement. Sure, updates create some incompatibilities sometimes, but it’s nowhere near extremely difficult. I mean FBW had a day-one patch.
I can understand wanting some of the ILS bugs fixed, but ATC? NAV? “Study-level” airliners most often include a custom codebase for handling NAV functionality. ATC is not relevant to aircraft development.
Source?