Helpful page for distribution maintainers.
Also worth to have look at known issues page.
MATE only supports the current stable release.
For instance, 1.6 was released so 1.4 is no longer supported. When 1.8 is released, 1.6 will no longer be supported.
NotShowIn Changes, to hide different desktop apps, that MATE supports on it's own. Mostly xfce4/lxde changes