What You Need to Know First

  • Proxmox VE 9 is based on Debian 13 “Trixie.”
  • This is an in-place upgrade via apt — not a reinstall.
  • You must be running the latest Proxmox VE 8.x (preferably 8.4) before starting.
  • Back up everything (VMs, CTs, and /etc configs).
  • Test upgrades on a non-production node if possible.
  • Remove or disable any unsupported third-party repositories and packages.

The following commands will be run directly from the Proxmox shell. You can access it through the web interface under Shell or by connecting via SSH. Make sure you have root privileges before starting so each step completes without permission issues.

Step-by-Step Upgrade Summary

1. Run the Upgrade Checklist

Use the built-in script to detect and fix potential issues.

pve8to9
pve8to9 --full

2. Migrate or Shut Down VMs/CTs if Needed

If your host is part of a cluster, migrate running guests to another node to minimize downtime.

3. Update Your Current System

Make sure everything is up to date before switching repositories.

apt update
apt dist-upgrade
pveversion

Ensure your Proxmox version is 8.4.1 or newer.
If you use Ceph, upgrade to Ceph Squid (v19.2) before continuing.

4. Update Repository Definitions

You’ll switch from Bookworm → Trixie and update the Proxmox and Ceph repositories.

Update Debian Base Repositories

sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/pve-enterprise.list

Add the No-Subscription Repository

cat > /etc/apt/sources.list.d/proxmox.sources <<EOF
Types: deb
URIs: http://download.proxmox.com/debian/pve
Suites: trixie
Components: pve-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Then update:

apt update
apt policy

5. Perform the Upgrade

apt dist-upgrade

During the upgrade:

  • You’ll be asked about configuration files and service restarts.
  • You can generally accept defaults, but review key files such as /etc/issue, /etc/ssh/sshd_config, /etc/default/grub, and /etc/lvm/lvm.conf.
  • After completion, rerun the checklist:
pve8to9 --full

Then reboot:

reboot

And that’s it. Your Proxmox server is now running version 9 on Debian 13 Trixie. It takes a bit of patience to get through everything, but now you’re set with the newest updates and a more stable system.

Check out this video guide from Virtualize Everything