All nodes inside the cluster have exactly this following version:

[CODE]~# pveversion -v

proxmox-ve: 6.4-1 (running kernel: 5.4.65-1-pve)

pve-manager: 6.4-5 (running version: 6.4-5/6c7bf5de)

pve-kernel-5.4: 6.4-1

pve-kernel-helper: 6.4-1

pve-kernel-5.4.106-1-pve: 5.4.106-1

pve-kernel-5.4.65-1-pve: 5.4.65-1

pve-kernel-5.4.44-1-pve: 5.4.44-1

pve-kernel-4.15: 5.4-18

pve-kernel-4.15.18-29-pve: 4.15.18-57

pve-kernel-4.15.18-21-pve: 4.15.18-48

pve-kernel-4.15.18-12-pve: 4.15.18-36

ceph: 15.2.11-pve1

ceph-fuse: 15.2.11-pve1

corosync: 3.1.2-pve1

criu: 3.11-3

glusterfs-client: 5.5-3

ifupdown: 0.8.35+pve1

ksm-control-daemon: 1.3-1

libjs-extjs: 6.0.1-10

libknet1: 1.20-pve1

libproxmox-acme-perl: 1.0.8

libproxmox-backup-qemu0: 1.0.3-1

libpve-access-control: 6.4-1

libpve-apiclient-perl: 3.1-3

libpve-common-perl: 6.4-2

libpve-guest-common-perl: 3.1-5

libpve-http-server-perl: 3.2-1

libpve-storage-perl: 6.4-1

libqb0: 1.0.5-1

libspice-server1: 0.14.2-4~pve6+1

lvm2: 2.03.02-pve4

lxc-pve: 4.0.6-2

lxcfs: 4.0.6-pve1

novnc-pve: 1.1.0-1

proxmox-backup-client: 1.1.5-1

proxmox-mini-journalreader: 1.1-1

proxmox-widget-toolkit: 2.5-3

pve-cluster: 6.4-1

pve-container: 3.3-5

pve-docs: 6.4-1

pve-edk2-firmware: 2.20200531-1

pve-firewall: 4.1-3

pve-firmware: 3.2-2

pve-ha-manager: 3.1-1

pve-i18n: 2.3-1

pve-qemu-kvm: 5.2.0-6

pve-xtermjs: 4.7.0-3

qemu-server: 6.4-2

smartmontools: 7.2-pve2

spiceterm: 3.1-1

vncterm: 1.6-2

zfsutils-linux: 2.0.4-pve1[/CODE]