In 1965 Citroën upgraded their DS 19 with a 2175 cc engine with minor updates to the brake and suspension.
In 1968 the DS 21 used covered headlights with optional directional driving lights that swiveled up to 80° to match the steering direction. Furthermore the main lights were suspended to absorb suspension movement. In the US, the design was modified back to an open headlight design.
In 1968 the DS 21 was sold alongside the DS 21 IE which featured a Bosch D-Jetronic electronic injection system that raised overall power to 139 bhp.