In the current master the constructor is missing. Is this on purpose? I'm using PHP 5.4.7 on Windows in a Symfony project and neither using the swiftmailer without any charset definition nor setting $message->setCharset('utf-8') works for me. I get the now famous Charset "" not supported. NativeQpContentEncoder only supports "utf-8" - error.

Only hardcoding the private $charset='utf-8' in this class solves my problems. So mybe there are some circumstances (esp. on Windows) where this constructor is necessary.