Which Firefox Versions Does Firefox Color Support?

Updated

Firefox Color is described by its source as a theming experiment for Firefox Quantum and beyond. In practice, that means it targets the Firefox releases built on the Quantum engine—the modern generation of Firefox—rather than older pre-Quantum versions. If you are running a current or recent Firefox release, you are in the intended audience; if you are on a legacy version from before Quantum, the experiment is not aimed at you. Because the site is a live experiment, confirm the current compatibility details on color.firefox.com before relying on it.

What “Firefox Quantum and Beyond” Means

Firefox Quantum was the name given to a major Firefox rebuild that shipped with Firefox 57 in late 2017. It introduced a new rendering engine and a redesigned interface. “And beyond” signals that the experiment is meant to keep working with Firefox releases that came after that point, not just the first Quantum version.

So the practical reading is:

  • Supported in intent: modern Firefox releases (Quantum-era and later).
  • Not the target: pre-Quantum Firefox versions, which predate the theming approach this experiment uses.

How to Check Whether Your Firefox Works

  1. Open Firefox and go to the menu, then Help → About Firefox (or the equivalent about page) to see your version number.
  2. Confirm you are on a current release rather than a legacy build.
  3. Visit color.firefox.com and look for any compatibility notes or version requirements shown on the live site.
  4. If the site loads and offers the theme-building interface, your browser is in the supported range.

Expected result: you can reach the theme editor and preview changes. If the page fails to load properly or shows a compatibility warning, your version is likely outside the intended range.

Common Pitfalls

  • Assuming any Firefox works. The source frames this as an experiment tied to Quantum and later, so very old installs are not covered.
  • Treating the description as a guarantee. The wording is broad (“and beyond”), and the site is a live experiment—details can change. Check the site itself for the current state.
  • Confusing the browser version with the theme. Compatibility is about your Firefox build, not about which colors or theme you choose.

Bottom Line

Use Firefox Color if you are on a modern, Quantum-era or later Firefox release. For anything older, or if you want certainty about the exact current version support, check color.firefox.com directly, since it is the authoritative source for this experiment.