Firefox users need to update their browsers immediately due to the impending expiration of a critical security certificate.
Mozilla Urges Firefox Users to Update the Browser Immediately
TheMozilla blogreveals that on June 24, 2025, a Firefox root certificate will expire.
The expiration of the certificate could break Firefox add-ons and extensions. An officialMozilla support documentexplains:

A root certificate is a trusted authority that verifies the authenticity of websites, add-ons and software updates. When it expires, systems relying on that certificate can no longer verify these items, which may cause features like add-ons or secure media playback to stop working.
Firefox users must update to Firefox version 128 (or later) or Firefox ESR version 115.13 (or later) to avoid the expired root certificate.

Why Updating Firefox Is So Important
Basically, once Mozilla’s root certificate expires (and if you don’t update), Firefox becomes considerably more vulnerable because it will stop receiving the latest security updates. It may stop receiving DRM-protected content, as the browser security isn’t verified.
5 Hidden Dangers of Browser Extensions
Browser add-ons can greatly enhance your online experience, but they can also be threats to your security and privacy.
An out-of-date Firefox browser may also be exposed to malicious add-ons, untrusted certificates, and even compromised passwords.
How to Update Mozilla Firefox
If the prompt to update Firefox doesn’t appear, head toMenu > Help > About Firefox. If an update is available, install it, then restart your browser.
Finally, if you’re experiencing issues updating Firefox or with the root certificate expiration, there is an officialMozilla support forumthread filled with tips and guidance on the process.