Proxmox Backup Server 4.1 with modernized foundation

With version 4.1, Proxmox takes its backup server to a new level in terms of technology and functionality. The latest Debian base, a modern kernel, and targeted improvements in bandwidth control, verification, and S3 connectivity make this version particularly interesting for professional and heavily utilized backup environments.

Proxmox introduced a new version of its backup solution in November 2025. Proxmox Backup Server 4.1 is based on Debian 13.2 “Trixie” and thus offers an updated system base with more modern packages, improved hardware compatibility, and increased security. The package includes the Linux kernel 6.17 and ZFS 2.3, which means the system continues to be clearly geared towards professional storage and data center requirements.

In terms of content, version 4.1 focuses on greater control and efficiency during operation. Bandwidth control has been expanded and can now be applied not only to networks but also to users. This allows backup and recovery processes to be prioritized, for example, for productive systems over test environments.

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Backup verification has also been optimized: Administrators can now specify how many threads to use for reading data and calculating checksums. This allows for better adaptation to existing hardware and can significantly reduce runtime. In addition, S3-compatible object storage can now be connected with fixed bandwidth limits to avoid bottlenecks in shared networks.

The new version is available as a complete ISO image and can be installed directly or updated via package upgrade. Proxmox Backup Server remains free software under AGPLv3, but is supplemented for professional use by paid support subscriptions that include updates and technical enterprise support.