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.

Failing to update Firefox before next March means losing features relying on remote functionality. Many installed add-ons will become disabled, and other systems that require content verification could also break. The issue affects Firefox editions for Android and Windows operating systems, including Windows, macOS, and Linux. Those with iPhone or iPad versions of Firefox should be okay.