For update the module from the sandbox version follow this steps:
- Update to the latest sandbox version. (It's undocumented, but probably run the update.php is enough, if necessary).
- Disable the sandbox module, then delete it. (Don't uninstall it!)
- Enable the 7.x-1.0-unstable1 version of the 'mcc' module.
- Copy the data from the 'mailchimp_campaign_node_campaigns' database table to 'mcc_node_campaigns' table. (Probably the best way is dump the table, substitute the table names, and import the data.)
- If there is a newer version of 'mcc' module, after this steps you can update on the usual way.