: Developers sometimes use it to test how legacy sites render on the Gecko 1.9.2 engine.

: Click the link ending in .exe (Windows) or .dmg (Mac) to begin the download.

: Click the folder corresponding to your language (e.g., en-US for US English).

: After installation, disconnect from the internet before launching. Once open, go to Settings > Advanced > Update and select "Never check for updates" to prevent it from automatically upgrading to a modern version. Why Use Firefox 3.6?

: Scroll through the list and click on the folder labeled 3.6 (or a specific point release like 3.6.28 for the final update of that branch). Choose Your Operating System : Windows : Select the win32 folder. Mac : Select the mac folder. Linux : Select linux-i686 or linux-x86_64 .

: It was the last major version to support older operating systems like Windows XP SP2 and older Mac OS X versions.

While mostly obsolete, some users still seek version 3.6 for specific technical reasons: