Mozilla released the next major version of Firefox ESR (Extended Support Release), which has some notable implications. I would expect the fleet to be mostly updated to FF60 ESR any time between “now” and a week-ish from now.

For the major changes:

• NPAPI support has (finally) been removed, in line with every other major browser. This means plugins such as Java, Silverlight, etc cannot be run in Firefox. A message went out to Banner users on Monday of this week informing them that the recommended web browsers are IE (Windows) and Safari (macOS) as of today.
• If folks are noticing that the browser seems dramatically snappier, they’re right! Firefox ESR now uses the updated multi-threaded rendering engine (Branded as “Quantum” and originally rolled out in Firefox 57).
• Updated addon system. With the multi-threaded rendering engine, a side effect is existing addons (e.g. uBlock Origin, NoScript, etc) have to be rewritten. For many addons they’ve already been rewritten — FF57 rolled out back in November and changes were communicated to addon authors 6-12+ months prior to that. In some cases addons have not been rewritten due to authors abandoning them, or because the new addon system does not permit what it was trying to do. For those addons there’s not much to be done other than looking for a compatible addon that replicates the functionality if possible.
  • There are “forked” versions from older Firefox builds that still support NPAPI plugins and the legacy addon system – please do not install these for customers as they also tend to be significantly behind on security updates.

If a customer is running the “non-ESR” version of Firefox, this is all old news as these changes happened in November.