Short answer YES. It has always been possible to run multiple versions of Firefox using different profiles, but that is not something this forum and its related Knowledge Base explicitly supported; it has been considered an advanced procedure. What is now the developer edition was previously known Aurora, & it still uses that name for its update channel. It now however automatically installs alongside Firefox release and creates its own profile. So it is now automatically completing steps that previously were good practice or essential, but had to be done manually. Some background articles * [[Recover lost bookmarks on Firefox Developer Edition]] * https://developer.mozilla.org/en-US/Firefox/Developer_Edition * http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox * http://kb.mozillazine.org/Testing_pre-release_versions {not yet updated specifically to mention Developer edition)