public function checkOperationality()
    {
        // First check for curl requirements
        parent::checkOperationality();

        $options = $this->options;

        $apiVersion = $options['api-version'];

        if ($apiVersion == 0) {
            if (!empty($this->getApiKey())) {
                // if secret is set, we need md5() and md5_file() functions
                if (!function_exists('md5')) {
                    throw new ConverterNotOperationalException(
                        'A secret has been set, which requires us to create a md5 hash from the secret and the file ' .
                        'contents. ' .
                        'But the required md5() PHP function is not available.'
                    );
                }
                if (!function_exists('md5_file')) {
                    throw new ConverterNotOperationalException(
                        'A secret has been set, which requires us to create a md5 hash from the secret and the file ' .
                        'contents. But the required md5_file() PHP function is not available.'
                    );
                }
            }
        } elseif ($apiVersion == 1) {
            if ($options['crypt-api-key-in-transfer']) {
                if (!function_exists('crypt')) {
                    throw new ConverterNotOperationalException(
                        'Configured to crypt the api-key, but crypt() function is not available.'
                    );
                }

                if (!defined('CRYPT_BLOWFISH')) {
                    throw new ConverterNotOperationalException(
                        'Configured to crypt the api-key. ' .
                        'That requires Blowfish encryption, which is not available on your current setup.'
                    );
                }
            }
        }

        if ($this->getApiUrl() == '') {
            throw new ConverterNotOperationalException(
                'Missing URL. You must install Webp Convert Cloud Service on a server, ' .
                'or the WebP Express plugin for Wordpress - and supply the url.'
            );
        }
    }