Si toi aussi tu es forcé de maintenir une vieille appli qui a besoin de Java+Firefox et que les pop-ups de mise en garde te font chier:

CAUTION: These steps deactivate the Firefox blocklist for vulnerable plugins and extensions. Furthermore, vulnerable add-ons will NOT be blocked anymore. Use at your own risk!

- Type about:config into Location bar.
- Proceed by clicking the button "I'll be careful, I promise!".
- Rightclick, to toggle the string extensions.blocklist.enabled from true to false.
- Restart Firefox.