To compile the Bootstrap 3.0.3 LESS files used in this book, your chosen compiler must be updated to at least version 1.3.3 of less.js. If you will be downloading the latest version of Bootstrap (version 3.1.0 as of this writing), you will need a compiler updated to at least version 1.6.0 of less.js. At the time of writing this, updated compilers include: >WinLESS (free for Windows) http://winless.org/lessc >The LESS App (free for Mac) http://incident57.com/less/ >CodeKit (for Mac) http://incident57.com/codekit/ >grunt-contrib-less (requires Node) https://github.com/gruntjs/grunt-contrib-less