They took the 737, a design from the 1960s , and strapped massive, fuel-efficient engines onto it.
When you download a file and it gets corrupted, you get a "CRC Error." The data doesn't match the checksum. Something is broken.
But the moral case is even uglier:
A central theme of the film is the . This software was designed to automatically push the aircraft's nose down to prevent a stall, a necessity due to the larger engines on the 737 MAX that altered the plane's aerodynamics.