See this article about how to install multiple versions on Mac OS X:

• http://www.businessinsider.com/how-to-run-firefox-4-and-3-simultaneously-in-mac-os-x-with-multiple-firefox-profiles-2011-3

Use the -no-remote command line switch to open another Firefox instance with its own profile and run different Firefox instances simultaneously, but do not use -no-remote to start the default browser with the default profile.

• http://kb.mozillazine.org/Opening_a_new_instance_of_Firefox_with_another_profile

• http://kb.mozillazine.org/Profile_Manager#Creating_a_new_profile
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox

OK. But is there any way you can make one version always open with the first profile, the other - with the second, without doing it through Terminal and the profile manager. So firefox 27 opens with default when I click it and Aurora opens with Aurora when I click it? (aurora and default are profile names)

Thank you.

You will have to make specific shortcuts to open a Firefox instance with a specific profile by adding -P "profile name" to the command line to launch Firefox. If no profile is specified then the profile that is selected as the last used profile in the Profile Manager will be used. It is not possible to select another profile automatically if another profile is already being used. You will have to click the correct desktop shortcut to select a specific profile.