For future reference, because Kali is using a rolling release model:
To use the latest version - all you have to do is stay up to date with the updates. You don't need to worry about messing with sources.list whenever there is a new point-release.
Periodically, the developers of Kali might release a new point-release version of their live-CD / installer images. But that would only be for new installs.
For people wanting to install a fresh copy of Kali.
For existing installs, you just need to keep it up to date using apt. So most updates will just come from a quick "apt update && apt upgrade".
If you see any messages from "apt upgrade" that say anything about packages that were held back or not upgraded - the chances are there is a major update/upgrade available via "apt dist-upgrade", or "apt full-upgrade".
On a debian-based rolling release distro - upgrading to the latest version really is as simple as that! There is no need to change the default sources.list - unless the connection to the main repo is too slow. In which case - update sources.list to use one of their official mirrors that is situated nearer to where you live.
Thanks Jaskinasis, your right about that, I remembered the last time I messed with the sourece.list was because the connection was poor due to my location but for some reason now the connection has improved a lot. Everything's perfect again.