public function getChanges(array $params = [])
    {
        $path = '/'.$this->databaseName.'/_changes';

        $method = ((!isset($params['doc_ids']) || $params['doc_ids'] == null) ? 'GET' : 'POST');
        $response = '';

        if ($method == 'GET') {
            foreach ($params as $key => $value) {
                if (isset($params[$key]) === true && is_bool($value) === true) {
                    $params[$key] = ($value) ? 'true' : 'false';
                }
            }
            if (count($params) > 0) {
                $query = http_build_query($params);
                $path = $path.'?'.$query;
            }
            $response = $this->httpClient->request('GET', $path);
        } else {
            $path .= '?filter=_doc_ids';
            $response = $this->httpClient->request('POST', $path, json_encode($params));
        }
        if ($response->status != 200) {
            throw HTTPException::fromResponse($path, $response);
        }

        return $response->body;
    }