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.
https://github.com/arkenfox/user.js/
Mozilla has been controversial as of late but they aren’t Microsoft. They want people to move to a stable release so they can stop having to maintain old code. Also modern Firefox has a lot of improvements and you need to use an actively supported browser to get security fixes.
Also you can toggle resist fingerprinting with https://addons.mozilla.org/en-US/firefox/addon/toggle-resist-fingerprinting/