Update Avada Version 3.8 to latest

Hi I encounter a Problem with the Avada Theme. How do i backup the theme and update it properly. I get the following Error after import:

> **wp-content\themes\Avada\framework\plugins\importer\importer.php** on line **885**

function fusion_slider_delete_dir($dirPath) {
    if (! is_dir($dirPath)) {
        throw new InvalidArgumentException("$dirPath must be a directory");
    }
(substr($dirPath, strlen($dirPath) - 1, 1) != '/') {
        $dirPath .= '/';
    }
    $files = glob($dirPath . '*', GLOB_MARK);
    foreach ($files as $file) {
        if (is_dir($file)) {
            self::deleteDir($file);
        } else {
            unlink($file);
        }
    }
    rmdir($dirPath);
}

@ThemeFusion_Support @ThemeFusion