@bdacasc
You have to change the interface name from ens160 to eth0 after migrating a Ubuntu VM from ESXi to XCP-NG.

The file yopu need to edit is /etc/netplan/00-installer-config.yaml

After that type:

sudo netplan apply

With that the network should work again

Just to give some short feedback about upgrade from 8.3 beta to 8.3rc2 via ISO:

1. Pool master upgraded fine after selecting "Upgrade existing installation"
2. 2nd host in pool asked for management network configuration after selecting "Upgrade existing installation", but after that everything upgraded fine
3. Both host show "cloud" instead a build number after the upgrade
   
4. Guest tools version number of/reseted to .2, but this is already discussed earlier

All in all very smooth upgrade and everything is running as before - great work from the Vates team !