Why i get fatal error when installing laravel octane swoole?

Question

i want to install swoole mode in laravel octane but when in use command : pecl install swoole

this error is happen

Fatal error: Array and string offset access syntax with curly braces is no longer supported in C:\xampp\php\pear\PEAR\Config.php on line 2095

what should i do ?

line 2095 :

    if (strlen($prepend) > 0) {
        if (OS_WINDOWS && preg_match('/^[a-z]:/i', $path)) {
            if (preg_match('/^[a-z]:/i', $prepend)) {
                $prepend = substr($prepend, 2);
            } elseif ($prepend{0} != '\\') {
                $prepend = "\\$prepend";
            }
            $path = substr($path, 0, 2) . $prepend . substr($path, 2);
        } else {
            $path = $prepend . $path;
        }
    }