Retrofitting is the updated replacement or modernization of machinery, equipment, lighting, etc. with new high-performance components.
Retrofits must be able to be carried out while retaining and without modifying the existing mechanical and electrical conditions.
In lighting technology, retrofit is used to replace lamps and lighting fixtures of older design with modern new LED fixtures, using the existing lamp sockets. In other words, the LED lamps are fitted with an old base so that they can be used directly without changing the fixture and base. The different voltage supply is compensated by electronic supply circuits in the lamp base.