You can find the current pre-stable release of ATS2 at:
http://www.ats-lang.org/Downloads.html#ATS_packages
I often need to add some functions to ATSLIB when doing a project.
Instead of releasing ATS2 formally for such minor changes, I decide
to put a pre-stable release on-line for people interested in trying
the project I am working on. For instance, the current pre-stable release is
needed for testing the linux kernel modules implemented in ATS2:
–Hongwei
PS: If you use the ATS2-github version, then you are already up-to-date.
There is
no need for you to install a pre-stable release.