retrofit

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”

Fit in or on an existing structure, such as an older house.

“The mansion was retrofitted with modern plumbing”

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”

Substitute new or modernized parts or equipment for older ones.

“The laboratory retrofitted to meet the safety codes”