The word "retrofit" means to modify or upgrade something old or existing to make it more efficient, functional, or in line with current standards or requirements. Full definition
A kit is available for $ 800 CAD, which we assume allows for retrofitting of existing bicycles. (treehugger.com)
Another great way to create green jobs is to boost funding for retrofits of old toilets, plumbing fixtures and water - using appliances to more efficient models. (treehugger.com)
But other plants have planned to invest big money in retrofits with the hope of keeping the coal fires burning. (news.nationalgeographic.com)