a component or accessory added to something after it has been manufactured

the act of adding a component or accessory to something that did not have it when it was manufactured; the court ordered a retrofit on all automobiles'

provide with parts, devices, or equipment not available or in use at the time of the original manufacture; They car companies retrofitted all the old models with new carburetors'

fit in or on an existing structure, such as an older house; The mansion was retrofitted with modern plumbing'

substitute new or modernized parts or equipment for older ones; The laboratory retrofitted to meet the safety codes'