1. Introduction

#Proxmox VE 9.x brings new features, security updates, and performance improvements.
You can #upgrade in two main ways:

Fresh install → Install PVE 9 from ISO, then restore backups.
In-place upgrade → Keep your system and update it to #Debian Trixie + PVE 9.

This guide focuses on the in-place upgrade from PVE 8.x (#Bookworm) to PVE 9.x (#Trixie).

⚠ Important:

Back up all VMs, containers, and configuration before starting.
Test in a lab environment if possible.
For production, plan downtime or do a node-by-node cluster upgrade.

https://syncbricks.com/proxmox-ve-8-to-9-upgrade-guide-debian-bookworm-to-trixie/

Proxmox VE 8 to 9 Upgrade Guide – Step-by-Step (Debian Bookworm to Trixie)

Learn how to safely upgrade Proxmox VE from 8.x (Debian Bookworm) to 9.x (Debian Trixie) using the official in-place method. Includes prerequisites, repository updates, commands, cluster tips, and troubleshooting.

^{Amjid Ali (SYNCBRICKS - Information Technology for everyone)}