how to upgrade laravel code example

Example 1: laravel update

<!-mass update-->
App\Models\Flight::where('active', 1)
          ->where('destination', 'San Diego')
          ->update(['delayed' => 1]);

Example 2: update laravel

use App\Models\Flight;

$flight = Flight::find(1);

$flight->name = 'Paris to London';

$flight->save();

Example 3: laravel update

$flight = App\Models\Flight::find(1);

$flight->name = 'New Flight Name';

$flight->save();

Example 4: laravel 7 upgrade

$>which composer
/usr/local/bin/composer

$>php -d memory_limit=512M /usr/local/bin/composer update
...