This week has it all in terms of virtualization and backup, hit by hit followed on 5.8 the release of the VE 9.0 and directly afterwards on 6 August 2025 of the PBS 4.0 A special day for the Proxmox community.
After the recently released beta versions, we can celebrate two major releases today: Proxmox VE 9.0 It was officially released yesterday and at the same time Proxmox Backup Server 4.0.
Both versions are based on the brand new Debian 13 ‘Trixie’ and bring with it many exciting innovations.
Note: Who mine Beta article from this week If you have read this, you can already consider it obsolete. The final releases are here and bring further improvements. I'll link them here.
Proxmox VE 9.0:
The Next Generation of Virtualization
Technical basis
The new version is based on the great Debian 13 ‘Trixie’ but uses a newer Linux kernel 6.14.8-2 as a stable standard in Proxmox VE. This solid foundation is complemented by updated versions of all important components:
- QEMU 10.0.2: Latest virtualization technology
- LXC 6.0.4: State-of-the-art container virtualization
- ZFS 2.3.3: Advanced file system features
- Ceph Squid 19.2.3: Modern storage cluster solution
The most important innovations in detail
1. Snapshots as Volume Chains Snapshots as volume chains provide vendor-independent support for snapshots on any storage system that supports block storage. This includes iSCSI and Fibre Channel SANs.
- Practical example: Previously, you were dependent on special storage systems for snapshots. With Volume Chains, you can now also snapshot to:
- iSCSI Storage create
- Fibre Channel SANs utility
- Any Block storage system using
2. HA rules for advanced cluster logic High-Availability (HA) rules for assigning resources to nodes and resources to each other.
- Use cases:
- Node affinity: Certain VMs should only run on specific nodes
- Resource affinity: Automatically place related services on the same nodes
- Anti-affinity: Distribute critical services across different nodes
3. SDN Fabrics for Software-Defined Networking Software-Defined Networking (SDN) Stack.
- What this means: Simplify the management of complex network infrastructures by:
- Automated VXLAN configuration
- Simplified Ceph full mesh setups
- Better integration of different network layers
4. Modernized mobile web interface A modernized mobile web interface written in the Rust programming language using the Yew web framework.
- highlights:
- Completely in rust newly developed
- Significantly better performance
- Native mobile experience
- Future-proof technology basis
5. ZFS 2.3.3 with RAIDZ extension ZFS 2.3.3 with support for adding new devices to RAIDZ pools without downtime.
- Practical benefits: You can now expand your RAIDZ pools without:
- Downtime the VMs
- Complex migration of data
- Risk of data loss
Proxmox Backup Server 4.0:
Enterprise backup redefined
The revolution: S3-compatible Object Stores
S3-compatible object storage as a backup storage backend (Technology Preview). Proxmox Backup Server can now connect to object stores that provide an S3-compatible API.
- Game-Changer for Enterprise Environments:
- Amazon S3: Direct integration with AWS infrastructures
- MinIO: On-premises S3-compatible storage solutions
- Cloudflare R2: Cost-effective cloud storage option
- Google cloud storage: Multi-cloud strategies possible
- Technical details:
- A new datastore type stores backup metadata and chunks in an S3 compatible object store.
- Local cache for optimized performance
- Virtually unlimited scaling
Automatic synchronization jobs
Allows synchronization jobs to be automatically executed as soon as a relevant removable datastore is connected.
- Scenario: USB hard drive for offsite backups:
- Connect USB disk to server
- Proxmox automatically detects the removable data store
- The sync job starts automatically
- Backup is created, USB disk can be safely removed
ZFS RAIDZ extension without downtime
The Backup Server also benefits from the ZFS 2.3.3 innovations. ZFS now supports adding new devices to existing RAIDZ pools without downtime.
Upgrade path and compatibility
For Proxmox VE 9.0
Can I use the latest Proxmox VE 8 on 9 with apt Updating?
Yes, go, but please follow the upgrade instructions: As the official forum says: The upgrade is seamless, but you should follow the comprehensive upgrade guide. RTFM ⁇ At first glance, I don't see any differences to the Beta upgrade.
Support period: Proxmox VE 8.4 will receive security updates and critical bug fixes by August 2026. So you have over a year to upgrade.
For Backup Server 4.0
Can I use the latest Proxmox Backup Server 3 to 4 with apt Updating? Yes, please follow the upgrade instructions. Here, too, a seamless upgrade is possible. Same same, but different! And also RTFM ⁇ Again, there seems to be no difference to the Beta upgrade process to give.
compatibility: We are actively testing the compatibility of all currently supported major versions, including the previous ones. This means that you can securely back up from Proxmox VE 8 to Proxmox Backup Server 4 or from Proxmox VE 9 to Proxmox Backup Server 3.
FAQ and links to releases
Backup Server 4.0 forums | upgrade & Proxmox VE 9.0 forums | upgrade
Why Debian 13? Debian 13 is scheduled for stable release next Saturday, August 9. However, its core components have been stabilised since the hard freeze on 15 May. Proxmox thus takes advantage of the fact that the core components have already been frozen for months and are ‘pretending’ a little.
Hardware recommendations for PBS 4.0 We recommend enterprise-grade server hardware components with fast local SSD/NVMe storage. Access and response times from rotating drives (or lovingly spinning Rust) will slow down all backup server operations.
Installation next to Proxmox VE possible? Can I install Proxmox Backup Server on Debian, in a VM, as LXC or together with Proxmox VE?
Yes, but all this is not the recommended setup (only for experts or Homelabs with limited hardware - Editor's note).
What these releases mean for practice
For small environments
- Mobile Web UI: Finally also reasonable management / insights from the smartphone
- Simplified HA rules: Even smaller clusters benefit from intelligent VM distribution
- S3 backup: Cost-effective cloud backup strategies possible
For enterprise environments
- S3 integration: Seamless integration into existing cloud infrastructures
- Volume chain snapshots: Avoid vendor lock-in in storage
- SDN Fabrics: Simplify complex network topologies
For service providers
- Multi-tenant skills: Improved isolation thanks to advanced SDN functions
- Scalable backup solutions: S3 backend scales virtually unlimited
- automation: Removable datastore sync reduces manual effort
Outlook and recommendations
This double release marks an important milestone for the Proxmox ecosystem. Especially the S3 integration with the backup server and the modernized mobile UI at Proxmox VE show that Proxmox not only keeps the connection to modern cloud-native technologies, but actively promotes them.
My recommendation: Those who operate productive environments will wait a few more weeks with the upgrade, so that any childhood diseases can be fixed.
Do you have a Homelab or QM/Staging system? Let's go: Get started right away for test environments – the new features are definitely worth a look!
I personally find the S3 integration with the backup server particularly exciting. This opens completely new doors for hybrid cloud strategies and makes Proxmox interesting for many new use cases.
Both releases are now to download ready. Have fun people!
EN 
DE 
ES 
FR 
IT