Backdrop CMS : Put your content center stage.
Backdrop CMS is an Open source, community-developed CMS (content management system) written in PHP and licensed under the GNU General Public License. Backdrop CMS was forked from the Drupal CMS in 2013 by two Drupal developers, Nate Lampton (née Nate Haug) and Jen Lampton. The backdrop is similar to version 7 of the Drupal CMS, maintaining the same functionality and features. The project's mission is to "enable people to build highly customized websites affordably, through collaboration and open source software."
Features
Built-in upgrade from Drupal 7.
Serve pages fast, even on shared hosting.
Add more functionality quickly.
Works great on phones & tablets.
Create and manage your content.
Control access with permissions.
Customize everything, everywhere.
Security is a priority.
Deploy changes easily.
Backdrop CMS is free software.