PHP Warning: Undefined array key “log_threshold” how to solve it?

Hello i have recently works on some script in localhost and whend i load the page i got “HTTP ERROR 500”

So i tried to look on apache logs and i saw this :[php:warn] [pid 6384:tid 1932] [client 127.0.0.1:63934] PHP Warning: Undefined array key "log_threshold" in C:\xampp\htdocs\xenfo.club\system\core\Log.php on line 138 [Fri Oct 06 09:00:39.006579 2023] [php:warn] [pid 6384:tid 1932] [client 127.0.0.1:63934] PHP Warning: Undefined array key "log_threshold" in C:\xampp\htdocs\xenfo.club\system\core\Log.php on line 142 [Fri Oct 06 09:00:39.261375 2023] [php:error] [pid 6384:tid 1932] [client 127.0.0.1:63934] PHP Fatal error: Array and string offset access syntax with curly braces is no longer supported in C:\xampp\htdocs\xenfo.club\public\src\service\Google_Utils.php on line 58 [Fri Oct 06 09:00:40.385679 2023] [php:warn] [pid 6384:tid 1952] [client 127.0.0.1:63933] PHP Warning: Undefined array key "log_threshold" in C:\xampp\htdocs\xenfo.club\system\core\Log.php on line 138, referer: https://xenfo.club/service_worker.js [Fri Oct 06 09:00:40.385679 2023] [php:warn] [pid 6384:tid 1952] [client 127.0.0.1:63933] PHP Warning: Undefined array key "log_threshold" in C:\xampp\htdocs\xenfo.club\system\core\Log.php on line 142, referer: https://xenfo.club/service_worker.js

So i go to look up on all the lines :
In log.php : line 138 to line 147

if (is_numeric($config['log_threshold']))
        {
            $this->_threshold = (int) $config['log_threshold'];
        }
        elseif (is_array($config['log_threshold']))
        {
            $this->_threshold = 0;
            $this->_threshold_array = array_flip($config['log_threshold']);
        }

in Google_Utils.php line 47 to line 59

// Include the top level classes, they each include their own dependencies
require_once 'service/Google_Model.php';
require_once 'service/Google_Service.php';
require_once 'service/Google_ServiceResource.php';
require_once 'auth/Google_AssertionCredentials.php';
require_once 'auth/Google_Signer.php';
require_once 'auth/Google_P12Signer.php';
require_once 'service/Google_BatchRequest.php';
require_once 'external/URITemplateParser.php';
require_once 'auth/Google_Auth.php';
require_once 'cache/Google_Cache.php';
require_once 'io/Google_IO.php';
require_once('service/Google_MediaFileUpload.php');

If someone know something pls help me to fix this

Frameworks: CodeIgniter (PHP)

Server: Xampp

An also i can’t find service_worker.js
Any idea to create one ?

Thanks in advance