Premise: The Ligier JS17 was a Formula One car designed by Gérard Ducarouge and Michel Beaujon for use by the Ligier team during the season. Powered by a Talbot-badged Matra V12, the JS17 was driven to two Grand Prix wins by Jacques Laffite. It was updated to JS17B specification for the season until it was replaced later that year by the JS19.
Hypothesis: The JS17B was not the last upgrade to the Ligier JS17.