1. past tense and past participle of retrofit; added new or modified parts or features to something already built or manufactured

1. having been equipped with new or modified parts or features after original construction or manufacture

Examples

• The old building was retrofitted with modern fire safety systems.
• They retrofitted the car with a new engine for better fuel efficiency.
• The retrofitted airplane included updated navigation equipment.
• Many homes were retrofitted with solar panels last year.
• The retrofitted factory now meets current environmental standards.
• Engineers retrofitted the bridge to withstand stronger earthquakes.