Mozilla is reminding Firefox users that a necessary root certificate expires soon and that older browser versions could become a security and usability nightmare in a few months. Starting March 14, 2025, Firefox versions older than 128 (ESR 115.13) containing the expired certificate will likely cause “significant” issues with add-ons, content signing, and streaming of DRM-protected media.
It should have been made clear to everyone back in 2019 when Mozilla let a signing certificate lapse, causing all extensions to be disabled for all users everywhere all at once that leaving your extensions at the mercy of Mozilla (a.k.a. Google’s lapdog) is a terrible idea.
about:addons
navigate to Gear icon
“Install addon from file…”