Undefined array key “HTTP_ACCEPT_LANGUAGE”

We’re receiving this warning on PHP 8.2:

PHP Warning:? Undefined array key "HTTP_ACCEPT_LANGUAGE" in /wp-content/plugins/countdown-builder/classes/countdown/CircleCountdown.php on line 182

I copied the change you made in SimpleCountdown.php to fix the same error, changing line 182 of CircleCountdown.php from this:

$lang = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);

to this:

$serverLang = '';
if (!empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
    $serverLang = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
}
$lang = substr($serverLang, 0, 2);

and that fixed it, but obviously we’d prefer a permanent fix in the plugin ?? Thanks!