Proxmox Mail Gateway 9.1 with improved security and quarantine tools

With version 9.1, the platform will be switched to Debian 13.5 Trixie and the Linux kernel 7.0 will be adopted as the standard stable version. To maintain high security standards, the developer has updated several critical open source components. These include SpamAssassin 4.0.2 with current rule sets, ClamAV 1.4.4 for virus scanning, PostgreSQL 17 for database management and ZFS 2.4 for file system stability.

Improved quarantine management

The web-based quarantine interface has been extensively redesigned to streamline workflows for both end users and system administrators.

For organizations using shared mailboxes, a new checkmark system allows users to mark items in quarantine as read, ensuring teams don't waste resources checking the same emails multiple times. In addition, the system now provides more transparency regarding the filtering process by displaying both the positive and negative elements of a spam rating at the same time.

Security and privacy have also been prioritized with the introduction of on-demand image loading. Instead of automatically loading external images, users must manually trigger the display, reducing the risk of remote tracking and malicious web content. Administrators can now also copy private links for quarantine access directly from the administration dashboard, simplifying the process of enabling secure access for specific users.

Advanced backup encryption

To better protect sensitive company data, version 9.1 introduces native encryption for backups targeting the Proxmox Backup Server. This feature ensures that data - including email configuration settings, custom rule sets and private statistics - is encrypted on the client side before it is transferred. This ensures that data remains encrypted even when at rest on the backup storage target.

Installation and business options

Proxmox Mail Gateway 9.1 is now available as open source software. It can be deployed via a dedicated ISO file for bare-metal installations, installed on existing Debian systems or run as a lightweight Linux container on Proxmox VE. For users currently running version 8.2 or 9.0, a tested upgrade path is available via the APT package management system.

Although the software is open source, Proxmox offers enterprise support plans for production environments that require stable updates and direct expert support. These plans start at €190 per host per year and cover an unlimited number of domains and users.