Rule source on GitHub

DowngradeExitNamedArgumentRector

Remove named argument from exit() and die()

-exit(status: 1);
+exit(1);

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\DowngradePhp84\Rector\FuncCall\DowngradeExitNamedArgumentRector;

return RectorConfig::configure()
    ->withRules([
        DowngradeExitNamedArgumentRector::class,
    ]);