Unexpected response field from Bunq API: "id" => "Id"

It seems Bunq has updated its API.

The documentation at https://doc.bunq.com/api/1/call/session-server/method/post

Suggests to return:

{

    "Response": [
        {
            "Id": {
                "id": 49
            }
        }
    ]
}

But it seems to return (note the casing of "id" => "Id":

{

    "Response": [
        {
            "Id": {
                "Id": 49
            }
        }
    ]
}

Since fetching the value is hard-coded to "id", this results in an error like:

Uncaught TypeError: Argument 1 passed to Link0\Bunq\Domain\Id::fromInteger() must be of the type integer, null given, called in /app/vendor/link0/bunq/src/Client.php on line 141 and defined in /app/vendor/link0/bunq/src/Domain/Id.php:27
Stack trace:
#0 /app/vendor/link0/bunq/src/Client.php(141): Link0\Bunq\Domain\Id::fromInteger(NULL)
#1 /app/vendor/link0/bunq/src/Client.php(120): Link0\Bunq\Client->mapResponse('Id', Array)
#2 /app/vendor/link0/bunq/src/Client.php(78): Link0\Bunq\Client->processResponse(Object(GuzzleHttp\Psr7\Response))
#3 /app/vendor/link0/bunq/src/Service/InstallationService.php(74): Link0\Bunq\Client->post('session-server', Array, Array)

link0 / bunq

Unexpected response field from Bunq API: "id" => "Id" #31