Getting error while updating slim

I am trying to update slim and getting below giving error. Please help.

Fatal error : Uncaught ArgumentCountError: Too few arguments to function Slim\App::__construct(), 0 passed in C:\xampp\htdocs\fotoschulebaur\index.php on line 15 and at least 1 expected in C:\xampp\htdocs\fotoschulebaur\vendor\slim\slim\Slim\App.php:62 Stack trace: #0 C:\xampp\htdocs\fotoschulebaur\index.php(15): Slim\App->__construct() #1 {main} thrown in C:\xampp\htdocs\fotoschulebaur\vendor\slim\slim\Slim\App.php on line 62

Are you trying to upgrade from Slim 3 to Slim 4?

In this case, you need to change how the Slim App instance is created.

For example.

Before, in Slim 3:

use Slim\App;

$app = new App();

In Slim4 change it to:

use Slim\Factory\AppFactory;

$app = AppFactory::create();
// ...

Read more: Slim 4 Upgrade Guide

i already change this