The message given by the "Database consistency check" suggest to destroy your data without any warning.

Please run the suggested SQL statements before upgrading.

The database is not consistent with the distribution database.

To synchronize your database with the distribution setup, run the following SQL commands:

DROP TABLE ezx_bouncedata;
DROP TABLE ezx_newsletter_subscription;
DROP TABLE ezxnewsletter;
DROP TABLE ezxnewslettertype;
DROP TABLE ezxsendnewsletteritem;
DROP TABLE ezxsubscription;
DROP TABLE ezxsubscription_group;
DROP TABLE ezxsubscription_list;
DROP TABLE ezxsubscriptionuserdata;