Easiest method to update a sub-theme.

Just updated Radix from 7.x-3.1 to Radix 7.x-3.3.

Is there a drush command to update a radix sub-theme. I know I am likely missing a command and see the steps posted to the Radix site - do we still follow those steps at: http://www.radixtheme.org/articles/update-rc4-to-3/, or is there an easier way.

Thanks,
Gregg