Noté 4 sur 5 étoiles

par Utilisateur ou utilisatrice c23238 de Firefox le août 15, 2017 · lien permanent

Only version 4.1 is compatible with FF 54 to 56, click on the "View other versions" text on this page and scroll down to version 4.1.
Before you install version 4.1, dont forget to uninstall the previous plugin even if its in disabled form, and restart firefox.
Install the new one only after you removed the old one and restarted.