In proxmox 6.2-4,how can i use my backup made from proxmox 7.1-4 ?

Hi,
in general it's not supported to restore a newer backup on an older system, because the old system might not have all the necessary features. What compression is the backup using?

P.S. Proxmox VE 6.x is EOL since last week, please upgrade to 7.x, here is the official guide.