First question: Is that form of the token, specifically having +\ at the end, correct and expected?

If I then take that token and execute

$createAccountToken = $response['query']['tokens']['createaccounttoken'];

$oauth->fetch("https://myserver/w/api.php?action=createaccount&format=json&name=FooBar&email=foobar@gmail.com&realname=FooBar&mailpassword=false&reason=provisioning&language=en&token=$createAccountToken", null, OAUTH_HTTP_METHOD_PUT);

I receive

{"error":{"code":"createnotoken","info":"The token parameter must be set","*":"See https://myserver/w/api.php for API usage"}}

Second question: What am I doing wrong when invoking the createaccount action?

I am following documentation at

https://www.mediawiki.org/wiki/API:Account_creation

but it is not clear to me which parts of that page may be deprecated and precisely how I should provision a new account.