less/less-plugin-clean-css — pull request #5 by bassjobsen (2014-12-25 00:58:54+00:00)
Title: options version 3x

As far as i understand the option should be changed according https://github.com/jakubpawlowicz/clean-css#how-to-upgrade-clean-css-from-2x-to-3x

Both `advanced` and `rebase` are set to false by default now.