The "KC s2M+MC Basic" plugin is now available in Russian, Bulgarian, which I translated, and Serbian, translated by Andrijana Nikolic. Contributions for other languages and improvements to the existing translations are welcome.
The update also adds lists of missing members. Below the "Check Synchronization" button, the plugin reports when a member exists on the site but not in the MailChimp list, or vice versa. The numbers in those messages are now links that open a pop-up containing the missing email addresses. You can use the list to search both the WordPress database and MailChimp and determine why the records are missing.
The release includes security improvements, so updating is recommended.
The requested-features list is becoming shorter, and new suggestions are welcome.