QSslSocket::setProtocol() does not work for TLS v1.2

void SslClient::secureConnect()
{
    if (!socket) {
        socket = new QSslSocket(this);
        connect(socket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
                this, SLOT(socketStateChanged(QAbstractSocket::SocketState)));
        connect(socket, SIGNAL(encrypted()),
                this, SLOT(socketEncrypted()));
        connect(socket, SIGNAL(sslErrors(QList<QSslError>)),
                this, SLOT(sslErrors(QList<QSslError>)));
        connect(socket, SIGNAL(readyRead()),
                this, SLOT(socketReadyRead()));
    }

    socket->setProtocol(QSsl::TlsV1_2); // New/Changed
    socket->connectToHostEncrypted(form->hostNameEdit->text(),
    form->portBox->value());
    updateEnabledState();
}