How To avoid the ugly, less functional, new Nova UI on Firefox.
In October 2026, without much warning, Mozilla rolled out a substantial user interface (UI) change, called Nova, to Firefox. Unfortunately, Nova is ugly and less functional than the prior refined UI called Proton.
Fortunately, there is a simple UI solution (at least for the next year or two), which is to switch from regular Firefox to Firefox ESR (Extended Support Release), which retains the classic UI and is more stable.
You can download ESR release 153.4.0 (not the earlier version) here:
You should then switch Settings > About Firefox > Firefox updates from Automatic (the default) to Check & choose, so that you can get security updates (for at least a year), but avoid a version update as long as possible (or until the new CEO comes to his senses).
ESR
Because enterprise customers demand stability, Mozilla has a separate, more stable release channel called Extended Support Release (ESR) that is updated infrequently except for security updates.
Backstory
Mozilla got a new permanent CEO in 2025, and he set about embracing AI and updating Firefox in an attempt to reverse its market share slide. Unfortunately, Mozilla had laid off and otherwise lost so much of its key development talent that he turned to 'easy' UI changes instead of hard core functionality improvements (like support for Progressive Web Apps) and bug fixes, so he could appear to be doing something. By aping more successful products he could claim to be making 'improvements' but while losing distinctiveness, which never works.
