Kali 2.0 is now available for download!, you can either download a fresh copy at: https://www.kali.org/downloads/
If you want to upgrade your old Kali to the new one you will need to edit your source.list entries, and run a dist-upgrade as shown below. If you have been using incorrect or extraneous Kali repositories or otherwise manually installed or overwritten Kali packages outside of apt, your upgrade to Kali 2.0 may fail. This includes scripts like lazykali.sh, PTF, manual git clones in incorrect directories, etc. – All of these will clobber existing files on the filesystem and result in a failed upgrade. If this is the case for you, you’re better off reinstalling your OS from scratch.
To upgrade your installation use the following commands:
cat << EOF > /etc/apt/sources.list
deb http://http.kali.org/kali sana main non-free contrib
deb http://security.kali.org/kali-security/ sana/updates main contrib non-free
apt-get dist-upgrade # get a coffee, or 10.