Would you like a more technical version (e.g., about about:config hacks or building old Firefox from source), or a fun “history of Firefox UI” piece instead?
There are several reasons why users may prefer to use old versions of Firefox: old version firefox
And somewhere in a VM, on a dusty hard drive, Firefox 3.6 is still running — proudly showing a single lonely tab: “You are in control.” Would you like a more technical version (e
Here’s the kicker: on older or low-RAM machines (think netbooks, old ThinkPads, or Raspberry Pi desktops), Firefox 52 ESR or 56 often modern browsers. No aggressive sandboxing per tab, no GPU compositor bloat, no background telemetry pinging. It just… renders. It just… renders
Snapshot 1.3.501.6 - Customizable UI themes | Vivaldi Browser
Using an old browser is like driving a classic car. It’s less safe, less efficient, and sometimes impractical — but it reminds you how much control we’ve traded for convenience. The web wasn’t always a locked-down app platform. Once, your browser was truly yours.
The primary reason users cling to old versions of Firefox—specifically versions prior to the "Quantum" update (version 57) in 2017—is the architecture of add-ons. For over a decade, Firefox was defined by its powerful extension system, XUL (XML User Interface Language). This system allowed developers to change almost every aspect of the browser. Extensions like "Classic Theme Restorer" or specific developer tools could dig deep into the browser’s skeleton. When Mozilla switched to the WebExtensions API to modernize the browser and improve stability, they effectively killed off thousands of legacy add-ons. For power users who relied on specific workflows that were only possible through these deprecated extensions, the "new" Firefox was functionally useless. Thus, they stayed behind, preferring a browser that worked their way over a browser that was modern.