After seven months of work, Concise v4 is now available to everybody. Quite a lot of things have happened since then. Here is a small overview:
The current development of Concise CSS is being handled by me (@jameskolce).
The framework has been almost completely rewritten, but the basic principles of being Concise are kept.
Now add-ons are completely independent of each other. Previously, they were included with the core, now they need to be installed separately with NPM or using the CDN.
A new add-on called Concise Utils has been added, with a lot of helper classes to improve the development workflow or to add context-dependant styles.
Concise UI is now written using the RSCSS guidelines.
The compilation of the source code is now done using the Concise CLI.
The compiler still uses Sass, but also includes some PostCSS plugins that will help with the development of websites.
A new lh unit is added to manage vertical rhythm. Using PostCSS-LH
Custom media queries are available, so you can write things like @media (--small).
Styles are automatically prefixed to work with older browsers, using Autoprefixer.
All the font sizes are now handled using the typeScale() function.
You can check the complete list of changes here: https://github.com/ConciseCSS/concise.css/compare/v3.4.0...master
And the new docs are already available at http://concisecss.com