Bug report

In PHPStan

'SimpleXMLElement::addChild' => ['static', 'name'=>'string', 'value='=>'string', 'ns='=>'string'],

In PHP documentation

public SimpleXMLElement::addChild(string $qualifiedName, ?string $value = null, ?string $namespace = null): ?SimpleXMLElement

When we give null as $value PHPStan raises an error.
I'd like to send a PR but how do I know in which PHP version was the change?

(PHP 5 >= 5.1.3, PHP 7, PHP 8)

Was it ?string from the beginning?
Please help me.

Expected output

No error.