Run Debian 13 as an LXC Guest on Proxmox 8

Debian 13 has been released on 9th of August of 2025.

However, Proxmox 8 cannot run an LXC guest with Debian 13, as it will result with an obscur error :

run_buffer: 571 Script exited with status 25
lxc_init: 845 Failed to run lxc.hook.pre-start for container "<CTID>"
__lxc_start: 2034 Failed to initialize container "<CTID>"
TASK ERROR: startup for container '<CTID>' failed

The fix is pretty simple. We need to edit the file /usr/share/perl5/PVE/LXC/Setup/Debian.pm and change around line 40 :

die "unsupported debian version '$version'\n" if !($version >= 4 && $version <= 13);

To

die "unsupported debian version '$version'\n" if !($version >= 4 && $version < 15);

Keep in mind that, since we edit a Proxmox File, it might be possible to re-instate this fix after an update.

However, this fix seems to be published in the latest PVE 9 version.