The kill switch seems to stem from the lack of updates to radar-jamming for the F-16 [0]. Lack of software support also, to me, suggests dropping hardware support (and the spare parts required) sooner rather than later. Even if it remains "only software", itself a hell of a phrase for this site, that software needs updates as Russia updates it's radar frequencies. The plane is potentially a hell of a lot less useful without the jamming capabilities they were sold with
[0] https://www.forbes.com/sites/davidaxe/2025/03/07/france-to-t...