Proxmox Mail Gateway 9.1 adds updated system components, changes to the spam quarantine interface, and encryption for backups. It works as a mail proxy positioned between the firewall and internal mail servers, screening incoming and outgoing traffic for spam, viruses, Trojans, and phishing attempts.
Updated system components
Version 9.1 runs on Debian 13.5 Trixie and ships with Linux kernel 7.0 as the stable default. The release includes SpamAssassin 4.0.2 with continuously updated rulesets, ClamAV 1.4.4, PostgreSQL 17, and ZFS 2.4. These versions track the current major open-source security packages that the platform depends on.
Quarantine interface changes
Several updates apply to the web-based quarantine, where administrators and end users review filtered messages. Within shared mailboxes, users can now mark quarantined emails as “seen,” which keeps teams from auditing the same message twice. The status appears inline as a checkmark and can be switched on or off with an action button.
The quarantine overview shows the positive and negative parts of an email’s spam score at the same time, giving administrators direct insight into the reasons a message crossed a filtering threshold.
External images in quarantined messages can be set to load only on demand. A user who wants to view those images clicks a “Load Images” button in the quarantine view. This lets staff inspect message content and keeps external image requests from firing automatically, which protects privacy and reduces exposure to web-based threats.
Administrators gain a “Copy Link” option on the admin dashboard. The option copies a recipient’s private quarantine access link, which an administrator can then pass along through any channel or build into a custom interface.
Encryption for backups
Version 9.1 adds native encryption for backups sent to a Proxmox Backup Server instance. The encryption covers email configuration settings, user-created rule system data, and historic and private statistics data. Proxmox Mail Gateway encrypts this material on the client side before it leaves the system, and it stays encrypted on the backup storage target.
Availability and pricing
Proxmox Mail Gateway 9.1 is open-source software and is available for download now. A complete ISO image carries the entire feature set and installs on bare-metal hardware through an installation wizard. Administrators can also place the software on an existing Debian system or run it as a Linux Container on Proxmox VE. Existing deployments on version 8.2 or 9.0 can move to 9.1 through a tested upgrade path in the APT package management system.
