wp-admin/includes/upgrade.php:1629Execute changes made in WordPress 2.7.
function upgrade_270() { global $wp_current_db_version, $wpdb; if ( $wp_current_db_version < 8980 ) { populate_roles_270(); } // Update post_date for unpublished posts with empty timestamp. if ( $wp_current_db_version < 8921 ) { $wpdb->query( "UPDATE $wpdb->posts SET post_date = post_modified WHERE post_date = '0000-00-00 00:00:00'" ); }}Introduced in 2.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/upgrade.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.