The tls, x509 and x509verify options were deprecated in QEMU v2.5.0:

commit 3e305e4a4752f70c0b5c3cf5b43ec957881714f7
Author:     Daniel P. Berrange <berrange@redhat.com>

    ui: convert VNC server to use QCryptoTLSSession

Use the tls-creds-x509 object when available.

https://bugzilla.redhat.com/show_bug.cgi?id=1598167Signed-off-by: NJán Tomko <jtomko@redhat.com>