This page is focused on upgrading from Sakai 12 to Sakai 19. It provides a link (below) to the Sakai 12 upgrade information that you will need if you are upgrading first to Sakai 12. Do that first and then come back here for the final steps to migrate to Sakai 19.
Please run ALL the scripts from your original version to the version to which you are upgrading. There are two sets of database upgrade scripts, one for MySQL and one for Oracle. Use the appropriate scripts for your database type.