<?php

class Stripe_Invoice extends Stripe_ApiResource
{
  public static function constructFrom($values, $apiKey=null)
  {
    $class = get_class();
    return self::scopedConstructFrom($class, $values, $apiKey);
  }

  public static function retrieve($id, $apiKey=null)
  {
    $class = get_class();
    return self::_scopedRetrieve($class, $id, $apiKey);
  }

  public static function all($params=null, $apiKey=null)
  {
    $class = get_class();
    return self::_scopedAll($class, $params, $apiKey);
  }

  public static function upcoming($params=null, $apiKey=null)
  {
    $requestor = new Stripe_ApiRequestor($apiKey);
    $url = self::classUrl(get_class()) . '/upcoming';
    list($response, $apiKey) = $requestor->request('get', $url, $params);
    return Stripe_Util::convertToStripeObject($response, $apiKey);
  }
}

<?php

class Stripe_Invoice extends Stripe_ApiResource
{
  public static function constructFrom($values, $apiKey=null)
  {
    $class = get_class();
    return self::scopedConstructFrom($class, $values, $apiKey);
  }

  public static function retrieve($id, $apiKey=null)
  {
    $class = get_class();
    return self::_scopedRetrieve($class, $id, $apiKey);
  }

  public static function all($params=null, $apiKey=null)
  {
    $class = get_class();
    return self::_scopedAll($class, $params, $apiKey);
  }

  public static function upcoming($params=null, $apiKey=null)
  {
    $requestor = new Stripe_ApiRequestor($apiKey);
    $url = self::classUrl(get_class()) . '/upcoming';
    list($response, $apiKey) = $requestor->request('get', $url, $params);
    return Stripe_Util::convertToStripeObject($response, $apiKey);
  }

  public function save()
  {
    $class = get_class();
    return self::_scopedSave($class);
  }

  public function pay()
  {
    $requestor = new Stripe_ApiRequestor($this->_apiKey);
    $url = $this->instanceUrl() . '/pay';
    list($response, $apiKey) = $requestor->request('post', $url);
    $this->refreshFrom($response, $apiKey);
    return $this;
  }
}

Add invoice pay and update methods
Add invoice pay and update methods
