protected function check_minmaxtouse() {
        global $CFG, $DB;
        require_once($CFG->libdir . '/gradelib.php');

        $userinfo = $this->task->get_setting_value('users');
        $settingname = 'minmaxtouse';
        $courseid = $this->get_courseid();
        $minmaxtouse = $DB->get_field('grade_settings', 'value', array('courseid' => $courseid, 'name' => $settingname));
        $version28start = 2014111000.00;
        $version28last = 2014111006.05;
        $version29start = 2015051100.00;
        $version29last = 2015060400.02;

        $target = $this->get_task()->get_target();
        if ($minmaxtouse === false &&
                ($target != backup::TARGET_CURRENT_ADDING && $target != backup::TARGET_EXISTING_ADDING)) {
            // The setting was not found because this setting did not exist at the time the backup was made.
            // And we are not restoring as merge, in which case we leave the course as it was.
            $version = $this->get_task()->get_info()->moodle_version;

            if ($version < $version28start) {
                // We need to set it to use grade_item, but only if the site-wide setting is different. No need to notice them.
                if ($CFG->grade_minmaxtouse != GRADE_MIN_MAX_FROM_GRADE_ITEM) {
                    grade_set_setting($courseid, $settingname, GRADE_MIN_MAX_FROM_GRADE_ITEM);
                }

            } else if (($version >= $version28start && $version < $version28last) ||
                    ($version >= $version29start && $version < $version29last)) {
                // They should be using grade_grade when the course has inconsistencies.

                $sql = "SELECT gi.id
                          FROM {grade_items} gi
                          JOIN {grade_grades} gg
                            ON gg.itemid = gi.id
                         WHERE gi.courseid = ?
                           AND (gi.itemtype != ? AND gi.itemtype != ?)
                           AND (gg.rawgrademax != gi.grademax OR gg.rawgrademin != gi.grademin)";

                // The course can only have inconsistencies when we restore the user info,
                // we do not need to act on existing grades that were not restored as part of this backup.
                if ($userinfo && $DB->record_exists_sql($sql, array($courseid, 'course', 'category'))) {

                    // Display the notice as we do during upgrade.
                    set_config('show_min_max_grades_changed_' . $courseid, 1);

                    if ($CFG->grade_minmaxtouse != GRADE_MIN_MAX_FROM_GRADE_GRADE) {
                        // We need set the setting as their site-wise setting is not GRADE_MIN_MAX_FROM_GRADE_GRADE.
                        // If they are using the site-wide grade_grade setting, we only want to notice them.
                        grade_set_setting($courseid, $settingname, GRADE_MIN_MAX_FROM_GRADE_GRADE);
                    }
                }

            } else {
                // This should never happen because from now on minmaxtouse is always saved in backups.
            }
        }
    }