Firefox 86 was released late yesterday, should auto-update for most users. Most interesting new feature could be Total Cookie Protection. The new feature is enabled automatically when you enable the strict mode of Firefox's Enhanced Tracking Protection feature:
Click on the shield shield detected to the left of the address bar on any webpage.
Click on Protection Settings. The Firefox Preferences Privacy & Security panel will open.
Under Enhanced Tracking Protection, select Strict.
Select the
Reload All Tabs button to apply your new privacy settings.
If something’s broken or not working when you use the Strict setting, you can use the toggle switch in the Shield panel to temporarily turn off protections on individual websites.
More info from Mozilla:
Enhanced Tracking Protection in Firefox for desktop