I shared this with my teams in discussion and just after we came up with a list of options for you, I showed the Nucleus come online and report back to our servers as 2.0.
Can you confirm?
Please note, you will need to update all other instances of Roon Remote to 2.0 for this to work.
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.