[pbs-devel] Proxmox Backup Server 4.0 released!

[Thomas Lamprecht]

Hi all!

We are pleased to announce the first stable release of Proxmox Backup Server
4.0 - immediately available for download!

The new version is based on the great Debian 13 "Trixie" but we're using a
newer Linux kernel 6.14.8-2 as stable default in Proxmox Backup Server,
including ZFS 2.3.3.

We're incredibly proud of the hard work that has gone into this release and
can't wait for you to experience it.

Some of the exciting new features we've packed into Proxmox Backup Server
4.0:

* S3-compatible object stores as backup storage backend (technology preview).
* ZFS 2.3 with RAID-Z expansion.
* Automatically trigger sync jobs when a removable datastore is mounted.
* and more...

Beyond these major additions, we've also implemented numerous performance
enhancements and bug fixes to make your experience even smoother. For a full
list of changes, check out our release notes.

Release notes
https://pbs.proxmox.com/wiki/Roadmap

Press release
https://www.proxmox.com/en/news/press-releases

Download
https://www.proxmox.com/en/downloads
Alternate ISO download:
https://enterprise.proxmox.com/iso

Documentation
https://pbs.proxmox.com/docs/

Community Forum
https://forum.proxmox.com

Bugtracker
https://bugzilla.proxmox.com

Source code
https://git.proxmox.com

There has been a lot of feedback from our community members and customers,
and many of you reported issues, submitted patches, and were involved in
testing - THANK YOU for your support!

FAQ
Q: Can I upgrade latest Proxmox Backup Server 3 to 4 with apt?
A: Yes, please follow the upgrade instructions on
   https://pbs.proxmox.com/wiki/Upgrade_from_3_to_4

Q: Can I upgrade an 4.0 beta installation to the stable 4.0 via apt?
A: Yes, upgrading from beta to stable installation is possible via apt. We
   recommend switching to the pbs-enterprise repository on upgrade for the
   most stable experience.

Q: How long will Proxmox Backup Server 3.4 receive bug fixes and security support?
A: Proxmox Backup Server 3.4 will receive security updates and critical bug
   fixes until August 2026. This support window provides an overlap of
   approximately one year after the release of Proxmox Backup Server 4,
   giving users ample time to plan their upgrade to the new major version.
   For more information on the support lifecycle of Proxmox Backup Server
   releases, please visit:
   https://pbs.proxmox.com/docs/faq.html#how-long-will-my-proxmox-backup-server-version-be-supported

Q: Why is Proxmox Backup Server 4.0 released ahead of the stable Debian 13
   release?
A: Debian 13 is scheduled for its stable release this Saturday, August 9.
   Its core components have been stabilized since it entered the "hard
   freeze" phase on May 15. Following extensive integration testing and
   valuable feedback during the Proxmox Backup Server 4.0 beta, we are
   confident in the stability of this release. Since our core packages are
   either maintained directly by the Proxmox team or are already locked by
   Debian's strict freeze policy, there is no technical reason to postpone
   our release.

Q: How does this integrate into Proxmox Virtual Environment?
A: Just add a Proxmox Backup Server datastore as a new storage target in
   your Proxmox VE. Make sure that you run the latest Proxmox VE 8.4 or
   Proxmox VE 9.0.

Q: Is Proxmox Backup Server still compatible with older clients or Proxmox
   VE releases?
A: We are actively testing the compatibility of all the major versions
   currently supported, including the previous one. This means that you can
   safely back up from Proxmox VE 8 to Proxmox Backup Server 4, or from
   Proxmox VE 9 to Proxmox Backup Server 3. However, full compatibility with
   major client versions that are two or more releases apart, like for
   example Proxmox VE 7 based on Debian 11 Bullseye and Proxmox Backup
   Server 4 based on Debian 13 Trixie, is supported on a best-effort basis
   only.

Q: How do I install the proxmox-backup-client on my Debian or Ubuntu server?
A: We provide a "Proxmox Backup Client-only Repository". See
   https://pbs.proxmox.com/docs/installation.html#client-installation
   For Debian derivatives we recommend installing the
   proxmox-backup-client-static package to avoid issues with different
   system library versions.

Q: Is there any recommended server hardware for the Proxmox Backup Server?
A: We recommend enterprise-grade server hardware components, with fast local
   SSD/NVMe storage. Access and response times from rotating drives will
   slow down all backup server operations. See
   https://pbs.proxmox.com/docs/installation.html#recommended-server-system-requirements

Q: Can I install Proxmox Backup Server on Debian, in a VM, as LXC or
   alongside with Proxmox VE?
A:Yes, but all this is not the recommended setup (expert use only).

Q: Where can I get more information about feature updates?
A: Check the roadmap https://pbs.proxmox.com/wiki/Roadmap

best regards
 Thomas