Verb
1. 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"2. fit in or on an existing structure, such as an older house;
"The mansion was retrofitted with modern plumbing"3. substitute new or modernized parts or equipment for older ones;
"The laboratory retrofitted to meet the safety codes"