I guess you could say the same about pronouns.

Anyway, why would someone use the spelling with upper D beats me. It's not proper English.

> I guess you could say the same about pronouns.

Entirely different thing. Software/things are not the same as people.

> why would someone use the spelling with upper D

SystemV, Zyklon B, Vampire hunter D, Plan B, Model T, Type O, ... It's extremely common.