Again, I have no information on how the 737 Max was certified. The only equivalency that I would mention is that at De Havilland Canada we had a product like the Dash 8 that evolved from a 37-seat aircraft to a 90-seat configuration today, which involved fuselage stretches and all these things. But they went through an incredibly robust process where new and current certification requirements would have to be applied to the aircraft. That aircraft has been in production for 20 years with nearly 700 built, so the process works.
I don't know about the 737, honestly.