global $wpdb;

	$wpdb->query( "UPDATE $wpdb->users SET user_activation_key = ''" );
}

/**
 * Execute changes made in WordPress 2.6.
 *
 * @ignore
 * @since 2.6.0
 *
 * @global int $wp_current_db_version The old (current) database version.
 */
function upgrade_260() {
	global $wp_current_db_version;

	if ( $wp_current_db_version < 8000 ) {
		populate_roles_260();
	}
}

/**
 * Execute changes made in WordPress 2.7.
 *
 * @ignore
 * @since 2.7.0
 *
 * @global int  $wp_current_db_version The old (current) database version.
 * @global wpdb $wpdb                  WordPress database abstraction object.
 */
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	// Update post_date for unpublished posts with empty timestamp.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'" );