Get off that old Firefox by Friday or you'll be sorry, says Moz

Mozilla warns that Firefox versions earlier than 128 (and ESR earlier than 115.13) must update by March 14 due to an expiring Mozilla root certificate that could disable add-ons, break DRM media playback, and degrade security features (e.g., blocklists, revocation lists, and preloaded intermediates); Windows, macOS, Linux, and Android are affected (iOS is unaffected), and Tor Browser users should also ensure they’re on a sufficiently recent release. Mozilla is simultaneously rolling out MRSP v3.0 to improve certificate revocation handling and require separate root CAs for TLS and S/MIME, with transition plans due by April 15, 2026 and full migration by December 31, 2028.