New release of Firefox come with fixes of all the issues ( http://www.mozilla.org/en-US/firefox/17.0/releasenotes/buglist.html) and one major change integration of Facebook in Firefox.

With the help of this we can get Facebook sidebar in Firefox .

How to enable Facebook messenger :

https://www.facebook.com/about/messenger-for-firefox

Download link :

http://www.mozilla.org/en-US/firefox/new/

[Update : 23/11/2012 ] Ubuntu user can directly update their Firefox using Ubuntu update Manager.