contain is deprecated/removed in 5.x as per https://book.cakephp.org/5/en/appendices/5-0-migration-guide.html#controller
For those with hundreds of controllers using this option it can be tedious to upgrade all at once. In that case one can use this one instead:
use Shim\Datasource\Paging\NumericPaginator;
/**
* @var array<string, mixed>
*/
protected array $paginate = [
'order' => ['States.modified' => 'DESC'],
'className' => NumericPaginator::class,
];