Woocommerce: Can't use sslv3 anymore? Using wp_remote_post

Question

I've been using the PSIGate payment Gateway built by Woothemes for WooCommerce. It's worked for a good two years, up until earlier this month my client's have been unable to process their credit cards. They get the following error:

There was an error while processing your request. Error Code: http_request_failed. Error Message: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol.

After doing some research, it looks like it's because we're using SSLv3, and the processor now only accepts TLS.

I'm diving into the plugin code, and this is how the API call is made:

/**
 * Process API request and return an XML object of the response
 *
 * @since 1.1
 * @param string $xml The XML string of the request
 * @return object|bool The SimpleXMLElement object of the response
 */
public function process_request( $xml, $url ) {

    $params = array(
        'method'    => 'POST',
        'sslverify' => false,
        'timeout'   => 120,
        'redirection'   => 0,
        'body'      => $xml,
    );

    $response = $this->send( $params, $url );

    return $response;

}

/**
 * Send the POST request and return the response
 *
 * @since 1.1
 * @param array $params
 * @return string
 * @throws Exception
 */
private function send( $params, $url ) {

    // Send the request and get the response
    $response = wp_remote_post( $url, $params );

    // If Error return the code and message
    if ( is_wp_error($response) ) {
        throw new Exception( sprintf( __( 'There was an error while processing your request. Error Code: %s. Error Message: %s.', WC_PsiGate::TEXT_DOMAIN ), $response->get_error_code(), $response->get_error_message() ) );
    }

    return $response;

}

They are using the wp_remote_post function to connect to PSI Gate. Do I need to convert this function to a CURL call? What would it look like?

Your help is much appreciated!