Actually this news already late for 3 days 🙂 because Kali Linux released at March 12, 2013.
Here is the news update from backtrack-linux.org:
Seven years of developing BackTrack Linux has taught us a significant amount about what we, and the security community, think a penetration testing distribution should look like. We’ve taken all of this knowledge and experience and implemented it in our “next generation” penetration testing distribution.
After a year of silent development, we are incredibly proud to announce the release and public availability of “Kali Linux“, the most advanced, robust, and stable penetration testing distribution to date.
Kali is a more mature, secure, and enterprise-ready version of BackTrack Linux. Trying to list all the new features and possibilities that are now available in Kali would be an impossible task on this single page. We therefore invite you to visit our new Kali Linux Website and Kali Linux Documentation site to experience the goodness of Kali for yourself.
We are extremely excited about the future of the distribution and we can’t wait to see what the BackTrack community will do with Kali. Sign up in the new Kali Forums and join us in IRC in #kali-linux on irc.freenode.net and help us usher in this new era.
About the difference between Backtrack Linux and Kali Linux the developer says it not an easy question to explain, they says :
It’s a mix between “everything” and “not much”, depending on how you used BackTrack.
From an end user perspective, the most obvious change would be the switch to Debian and an FHS-compliant system. What this means is that instead of having to navigate through the /pentest tree, you will be able to call any tool from anywhere on the system as every application is included in the system path. However, there’s much hidden magic in that last sentence. I’ll quickly list some of the new benefits of this move.