After your comment, i started to check the network side of things. Previously turned the firewall as you know but did not check the nucleus network config. I realized that, although there is no harm in static IP, external IP was somehow was pointing to a static IP as well, which does not work with the current ISP.
Anyhow, I changed to dynamic IP, rebooted it and nucleus automatically updated to latest version.
I can confirm that Nucleus is running 2.0 and I am once again enjoying the roon.
I am gratefull to your patience and support.
Next fight is the get ARC working, giving multiple NAT issue although in UPnP page i can see the correct port is listed automatically on router web ui.
Anyhow, this will be maybe another ticket, please kindly close this one, it is solved.