Updating your files
If you are upgrading your site from a previous release of Commerce Kickstart (since 2.x RC1 forward), we support an upgrade path.
IMPORTANT - Drush 8.x-6.x supports an upgrade for Kickstart 2, but it is not the common "drush up" command. Use the following code snippets (and make sure to backup everything):
$ drush dl commerce_kickstart $ drush updatedb -y
Or you can follow the step by step instructions below.