Move VM from 2.3 to 3.1 Host

Hi,

i want to move a VM from a 2.3 Host to a new 3.1 Host.
Is it only possible by Backup/Restore, or can i simply copy the conf file from "/etc/pve/nodes/proxmox/qemu-server" and the qcow2 File(s) from "/var/lib/vz/images"?
Or have i to note something special?


Alex