How to update proxmox latest LXC templates

Login to the pve server shell and run the following command :

# pveam update

After that it should be available for download (on the GUI).

Or you can download it manually from:

http://download.proxmox.com/images/system/

Ref :
https://forum.proxmox.com/threads/latest-lxc-templates-for-common-linux-distributions.25947/