Update Client

[adilhanomeronder]

[$access_token, $refresh_token] = $client->requestAccessToken(
    $redirect_uri,
    $code,
    $verifier
);

[$access_token, $refresh_token] = $client->refreshAccessToken($refresh_token);

 Hello, if I'm not mistaken, if we want to use it as above, we need to fix it this way, otherwise it gives the following error

 Notice: Undefined offset: 0 in and 1 in

[rhysnhall]

This is true prior to PHP 7.1.
PHP 7.1 onwards we can use arrays with keys for a list.
I'll update the requirements to specify that PHP 7.1 is the minimum supported version.