The bootstrap base theme is build on Twitter Bootstrap 2.3.0. A few months ago Twitter Bootstrap 3 was released offering some new and exciting features.
The most exciting feature is the 4 grid system. It is still the Bootstrap grid we were used to but with 4 different levels of responsiveness. The .spanx classes are replaced with .col-xs- (extra small) .col-sm-(small) .col-md- (medium) .col-lg- (large). Other elements like the carrousel, modals and collapsible items have been simplified. And most of the variables have been renamed.
Moving from Bootstrap 2 to 3 is no simple matter. Most of the less variable names have been replaced and some of the mixins have been removed / changed.However, I have made a start at migrating the bootstrapbase theme to Twitter Bootstrap 3 and after doing many find - replaces and rewrites of the Moodle less files I kind of got it working. I will release it as soon as the main bugs are solved (rtl layouts / icon fixes and more need to be worked on). My first attempt can be previewed here: http://theming.sonsbeekmedia.nl
This might be interesting for the bootstrapbase theme as well. There are a few pro's and cons of course.Pro: faster, cleaner, use grid on mobile, the way forward
Con: no YUI, many rewrites needed in moodle's less files
I am hoping others will want to jump in and help on this new project or help by adding your comments and ideas.
Screenshot of bootstrap 3 :