MAX (operating system)
MaX is a Linux distribution sponsored by the Office of Education of the autonomous Community of Madrid of Spain. MaX stands for Madrid LinuX. It used to be based on Ubuntu. Its last release, MaX 10, is based on Ubuntu 16.04 LTS "Xenial Xerus". Since 2003 MaX has been installed on all the computers of the schools in the Community of Madrid. MaX is an educational Linux with a large set of instructive programs in addition to usual desktop programs. MaX supports the most common desktop environments but, in MaX 10, MATE is installed by default. Main features are simplicity, stability and a huge collection of software. MaX comes as a Live DVD and an installable system, and as a USB version.

The changelog is here: http://ftp.rediris.es/mirror/MaX-Linux/MaXdesktop/MAX7.5/cambios.txt

External links

Homepage (in Spanish)
Distrowatch page
ISO images of MaX

References 
EducaMadrid web site

Educational operating systems
Spanish-language Linux distributions
State-sponsored Linux distributions
Ubuntu derivatives
Linux distributions