Copying a parallels instance is easy as copying the file from one machine to another.
But, this seems to screw up networking. The copied instance starts but a call to ifconfig -a shows no eth0 but a disconnected eth1 instead.
I’m guessing this is because the mac address the new version of parallels is supplying is different.
A way to fix is to edit /etc/udev/rules.d/70-persistent-net.rules
and remove the old card definition, and reassign eth0 to the new card
In hindsight a better thing to try would be to set the mac address to that of the original machine before starting the instance on the new machine.