TLS1.1 is not working in QT.4.7.4

We updated TLS 1.0 to TLS 1.1 . But our application ( QT 4.7.4 ) does not support TLS 1.1 .Currently we are using QNetworkManager to communicate with server and https is not atall hitting the server.so please suggest us how we can resolve this issue ?In Qt 5.x same code working perfectly and getting the data also.here is a sample code

Code:

void Downloader::doDownload()
 
{
manager = new QNetworkAccessManager(this);
  connect(manager, SIGNAL(finished(QNetworkReply*)),
  this, SLOT(replyFinished(QNetworkReply*)));
  manager->get(QNetworkRequest(QUrl("https://www.yahoo.com")));
 
}
void Downloader::replyFinished (QNetworkReply *reply)
{
        if(reply->error())
        {
                qDebug() << "ERROR!";
                qDebug() << reply->errorString();
        }
        else
        {
                qDebug() << reply->header(QNetworkRequest::ContentTypeHeader).toString();
                qDebug() << reply->header(QNetworkRequest::LastModifiedHeader).toDateTime().toString();
                qDebug() << reply->header(QNetworkRequest::ContentLengthHeader).toULongLong();
                qDebug() << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
                qDebug() << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
 
                QFile *file = new QFile("/root/NETWORK/tlsnet/ntwrkmangr/downloaded.txt");
                if(file->open(QFile::Append))
                {
                        file->write(reply->readAll());
                        file->flush();
                        file->close();
                }
                delete file;
  }
 
        reply->deleteLater();
}