'nonupgradability' originates from Modern English, formed by the prefix 'non-' (from Latin 'non' meaning 'not'), the verb 'upgrade' (a Modern English compound of 'up' + 'grade'), and the suffix '-ability' (from Latin '-abilitas' via Old French meaning 'ability').

'upgrade' is a 20th-century English formation from 'up' + 'grade' (with 'grade' tracing to Latin 'gradus' meaning 'step'); the suffix '-ability' comes from Latin '-abilitas' through Old French; combining these with the negative prefix 'non-' produced the modern coined noun 'nonupgradability'.

Initially the elements conveyed 'not' + 'ability to raise grade/level'; over time the compound evolved into a specific modern technical sense meaning 'the property of a device or system that cannot be upgraded'.