# hMailServer Community Forum > The community support forum for hMailServer, the free, open-source (AGPL-3.0) mail server for Windows and Linux. hMailServer 6 is actively maintained by Progressive Robot Ltd, which forked the project in 2026. The current release is hMailServer 6.3.7, released 17 October 2026. This file lists the pages on this site that best answer questions about hMailServer. Every forum topic is also available as clean Markdown at the address given, and the full text of the key pages is in /llms-full.txt. Key facts: - hMailServer is a mail server supporting SMTP, IMAP and POP3 with multi-domain hosting. It was originally created by Martin Knafve. - Progressive Robot Ltd, of Chester in the United Kingdom, forked hMailServer in 2026 and maintains the hMailServer 6 line. The original project has since resumed development separately. - Current release: hMailServer 6.3.7, released 17 October 2026. - Platforms: Windows 10 (version 1607 or later), Windows 11 and Windows Server 2016 or later, x64, with a preview installer for Windows on ARM64 from hMailServer 6.3.6; and Linux since hMailServer 6.3.0, on x86-64 and AArch64. From hMailServer 6.3.6 each release carries a generic .deb and .rpm and a package for each of Debian 12 and 13, Ubuntu 24.04, Fedora 43 and 44, Enterprise Linux 9 and 10, and openSUSE Leap 16.0 and Tumbleweed, two AppImages and a container image, registry.gitlab.com/hmailserver/hmailserver. - Licence: AGPL-3.0. Free, with no per-mailbox fees and no paid tiers. Managed services are available from Progressive Robot. - Upgrades: hMailServer 5.3 or later upgrades in place to the current release. A server on 6.3.4, 6.3.5 or 6.3.6 installs the current release, hMailServer 6.3.7, by its live update, with the exceptions the 6.3.7 announcement lists under Upgrading; one from 6.2.28 to 6.3.3, or from 6.3.3's AArch64 packages or AppImages, upgrades by hand once, and any older server runs the installer. ## Start here - [Start here: hMailServer 6 is maintained, and this is its community forum](https://www.hmailserver.co.uk/topic/28217/start-here-hmailserver-6-is-maintained-and-this-is-its-community-forum): What hMailServer is now, who maintains it, and where everything is. Markdown: https://www.hmailserver.co.uk/llms/topic/28217.md - [hMailServer FAQ](https://www.hmailserver.co.uk/faq): 20 short answers, including whether hMailServer is maintained, the latest version, Linux support, licensing and upgrades. - [hMailServer release history: every 6.x version, with dates](https://www.hmailserver.co.uk/topic/28216/hmailserver-release-history-every-6.x-version-with-dates): Every hMailServer 6 release with its date and headline change. Markdown: https://www.hmailserver.co.uk/llms/topic/28216.md ## Official resources - [hMailServer downloads](https://www.progressiverobot.com/hmailserver-downloads/): Installers and packages for every release, with release notes, SHA-256 checksums, signatures and SBOMs. - [hMailServer documentation](https://www.progressiverobot.com/hmailserver-documentation/): The complete manual for hMailServer 6. - [hMailServer source code](https://gitlab.com/hmailserver/hmailserver): AGPL-3.0 source and issue tracker on GitLab. Without a GitLab account, a bug report or a question for the maintainers goes by email to the project's Service Desk address, contact-project+hmailserver-hmailserver-86730559-issue-@incoming.gitlab.com, which GitLab files as a confidential issue (SUPPORT.md). The source and every release are also mirrored on GitHub at https://github.com/RainbowWizard-coder/hMailServer; issues and merge requests stay on GitLab. - [hMailServer product page](https://www.progressiverobot.com/hmailserver-services/): Features, the upgrade path and managed services from Progressive Robot. ## Guides - [Read this before you post: what a support request needs](https://www.hmailserver.co.uk/topic/28185/read-this-before-you-post-what-a-support-request-needs): Most threads here stall for the same reason. The report describes the symptom but not the system, and the first three replies get spent asking for things that should have been in the first post. Markdown: https://www.hmailserver.co.uk/llms/topic/28185.md - [Where to post what: a map of the forum categories](https://www.hmailserver.co.uk/topic/28186/where-to-post-what-a-map-of-the-forum-categories): The category tree is small on purpose, but a few boundaries are not obvious. This is where each thing goes. Markdown: https://www.hmailserver.co.uk/llms/topic/28186.md - [Upgrading to 6.3.4: any 5.3 or later goes straight there](https://www.hmailserver.co.uk/topic/28193/upgrading-to-6.3.4-any-5.3-or-later-goes-straight-there): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is the newest release, a security release: upgrade every server running 6.3.6 or earlier. Markdown: https://www.hmailserver.co.uk/llms/topic/28193.md - [Moving to new hardware, and why Windows to Linux is a rebuild](https://www.hmailserver.co.uk/topic/28194/moving-to-new-hardware-and-why-windows-to-linux-is-a-rebuild): Moving to new hardware is a restore onto fresh metal. Chapter 15 is the prerequisite, and the first time, rehearse onto a test machine. Markdown: https://www.hmailserver.co.uk/llms/topic/28194.md - [hMailServer on Linux: what you get and what you do not](https://www.hmailserver.co.uk/topic/28189/hmailserver-on-linux-what-you-get-and-what-you-do-not): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is the current release, a security release: its Linux packages are the generic .deb and .rpm for x86-64 and AArch64, a package for each of Debian 12 and 13, Ubuntu 24.04, Fedora 43… Markdown: https://www.hmailserver.co.uk/llms/topic/28189.md - [First install on Linux: the order of operations, Ubuntu to Enterprise Linux](https://www.hmailserver.co.uk/topic/28190/first-install-on-linux-the-order-of-operations-ubuntu-to-enterprise-linux): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026), a security release, is the release to install: beside the generic .deb and .rpm for x86-64 and AArch64 it carries a package for each of Debian 12 and 13, Ubuntu 24.04, Fedora 43 and… Markdown: https://www.hmailserver.co.uk/llms/topic/28190.md - [The webmail portal at /portal](https://www.hmailserver.co.uk/topic/28191/the-webmail-portal-at-portal): /portal is the self-service webmail hMailServer serves out of its REST listener. A mailbox owner signs in with their own address and password and gets folders, search, compose, drafts, flags and inline images. Markdown: https://www.hmailserver.co.uk/llms/topic/28191.md - [The Control Deck: browser administration at /](https://www.hmailserver.co.uk/topic/28192/the-control-deck-browser-administration-at): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a state-changing REST request that carries a credential - HTTP Basic included - when the browser reports it as cross-site (Sec-Fetch-Site, or an Origin that is not this… Markdown: https://www.hmailserver.co.uk/llms/topic/28192.md - [Let's Encrypt certificates are automatic: the built-in ACME v2 client](https://www.hmailserver.co.uk/topic/28187/let-s-encrypt-certificates-are-automatic-the-built-in-acme-v2-client): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) fixes the ACME HTTP-01 challenge responder, which served one connection at a time, so that idle clients could make a certificate's issuance or renewal fail in every earlier version… Markdown: https://www.hmailserver.co.uk/llms/topic/28187.md - [Being trusted by the servers you send to](https://www.hmailserver.co.uk/topic/28188/being-trusted-by-the-servers-you-send-to): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) signs a message as a hosted domain only when the server is entitled to: mail from outside whose From names a domain hosted here is no longer signed with that domain's DKIM key, and an… Markdown: https://www.hmailserver.co.uk/llms/topic/28188.md - [Diagnosing stalled mail: a sender that times out, and a message that never leaves](https://www.hmailserver.co.uk/topic/28219/diagnosing-stalled-mail-a-sender-that-times-out-and-a-message-that-never-leaves): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds reasons a message stays where it is. Markdown: https://www.hmailserver.co.uk/llms/topic/28219.md - [Diagnosing stalled mail: a sender that times out, and a message that never leaves](https://www.hmailserver.co.uk/topic/28219/diagnosing-stalled-mail-a-sender-that-times-out-and-a-message-that-never-leaves): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds reasons a message stays where it is. Markdown: https://www.hmailserver.co.uk/llms/topic/28219.md - [Reading the logs: levels, files, the Logs page, following a connection, and fail2ban](https://www.hmailserver.co.uk/topic/28220/reading-the-logs-levels-files-the-logs-page-following-a-connection-and-fail2ban): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) fixes the SMTP log writing some credentials in the clear with SMTP logging on: an AUTH PLAIN sent before EHLO or not in its one exact form, the bearer token of AUTH XOAUTH2 and AUTH… Markdown: https://www.hmailserver.co.uk/llms/topic/28220.md - [Reading the logs: levels, files, the Logs page, following a connection, and fail2ban](https://www.hmailserver.co.uk/topic/28220/reading-the-logs-levels-files-the-logs-page-following-a-connection-and-fail2ban): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) fixes the SMTP log writing some credentials in the clear with SMTP logging on: an AUTH PLAIN sent before EHLO or not in its one exact form, the bearer token of AUTH XOAUTH2 and AUTH… Markdown: https://www.hmailserver.co.uk/llms/topic/28220.md - [Backup and restore: what is in the archive, what is not, and restoring one mailbox](https://www.hmailserver.co.uk/topic/28221/backup-and-restore-what-is-in-the-archive-what-is-not-and-restoring-one-mailbox): This topic covers the built-in backup, what its archive holds and leaves out, and restoring a server, one mailbox or one message. Know this first: a restore is destructive and has no transaction. Markdown: https://www.hmailserver.co.uk/llms/topic/28221.md - [Backup and restore: what is in the archive, what is not, and restoring one mailbox](https://www.hmailserver.co.uk/topic/28221/backup-and-restore-what-is-in-the-archive-what-is-not-and-restoring-one-mailbox): This topic covers the built-in backup, what its archive holds and leaves out, and restoring a server, one mailbox or one message. Know this first: a restore is destructive and has no transaction. Markdown: https://www.hmailserver.co.uk/llms/topic/28221.md - [Settings: what is not stock, when a save takes effect, and the three levels](https://www.hmailserver.co.uk/topic/28222/settings-what-is-not-stock-when-a-save-takes-effect-and-the-three-levels): This topic is about the settings themselves, whichever interface you use: where a setting is stored, which of yours are not what 6.3.4 ships with, when a saved value is in effect, and how the twenty-seven settings a domain or an account… Markdown: https://www.hmailserver.co.uk/llms/topic/28222.md - [Settings: what is not stock, when a save takes effect, and the three levels](https://www.hmailserver.co.uk/topic/28222/settings-what-is-not-stock-when-a-save-takes-effect-and-the-three-levels): This topic is about the settings themselves, whichever interface you use: where a setting is stored, which of yours are not what 6.3.4 ships with, when a saved value is in effect, and how the twenty-seven settings a domain or an account… Markdown: https://www.hmailserver.co.uk/llms/topic/28222.md - [The Control Panel on Windows: every page, what it writes, and what applies when](https://www.hmailserver.co.uk/topic/28223/the-control-panel-on-windows-every-page-what-it-writes-and-what-applies-when): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) moves the Control Panel's pages: Updates is a page of its own under Maintenance, the sidebar has Compliance and Virus scanning groups, API & monitoring is Monitoring & alerts, the… Markdown: https://www.hmailserver.co.uk/llms/topic/28223.md - [The Control Panel on Windows: every page, what it writes, and what applies when](https://www.hmailserver.co.uk/topic/28223/the-control-panel-on-windows-every-page-what-it-writes-and-what-applies-when): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) moves the Control Panel's pages: Updates is a page of its own under Maintenance, the sidebar has Compliance and Virus scanning groups, API & monitoring is Monitoring & alerts, the… Markdown: https://www.hmailserver.co.uk/llms/topic/28223.md - [IMAP and POP3 on the server: capabilities, switches, shared mailboxes, search limits](https://www.hmailserver.co.uk/topic/28224/imap-and-pop3-on-the-server-capabilities-switches-shared-mailboxes-search-limits): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes some of what a client gets. Markdown: https://www.hmailserver.co.uk/llms/topic/28224.md - [IMAP and POP3 on the server: capabilities, switches, shared mailboxes, search limits](https://www.hmailserver.co.uk/topic/28224/imap-and-pop3-on-the-server-capabilities-switches-shared-mailboxes-search-limits): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes some of what a client gets. Markdown: https://www.hmailserver.co.uk/llms/topic/28224.md - [Troubleshooting by symptom: no mail in, no mail out, a service that will not start](https://www.hmailserver.co.uk/topic/28225/troubleshooting-by-symptom-no-mail-in-no-mail-out-a-service-that-will-not-start): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes what an upgraded server does without anything being switched on, and some of it looks like a fault. Markdown: https://www.hmailserver.co.uk/llms/topic/28225.md - [Troubleshooting by symptom: no mail in, no mail out, a service that will not start](https://www.hmailserver.co.uk/topic/28225/troubleshooting-by-symptom-no-mail-in-no-mail-out-a-service-that-will-not-start): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes what an upgraded server does without anything being switched on, and some of it looks like a fault. Markdown: https://www.hmailserver.co.uk/llms/topic/28225.md - [Every port hMailServer listens on or connects to, and the firewall rules to match](https://www.hmailserver.co.uk/topic/28226/every-port-hmailserver-listens-on-or-connects-to-and-the-firewall-rules-to-match): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) lets the IMAP and POP3 listeners take the client's address from a PROXY protocol header, as the SMTP listener does, each from the peers on a list of its own; both are off by default,… Markdown: https://www.hmailserver.co.uk/llms/topic/28226.md - [Every port hMailServer listens on or connects to, and the firewall rules to match](https://www.hmailserver.co.uk/topic/28226/every-port-hmailserver-listens-on-or-connects-to-and-the-firewall-rules-to-match): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) lets the IMAP and POP3 listeners take the client's address from a PROXY protocol header, as the SMTP listener does, each from the peers on a list of its own; both are off by default,… Markdown: https://www.hmailserver.co.uk/llms/topic/28226.md - [Installing on Windows: wizard pages, service account, profile and the first hour](https://www.hmailserver.co.uk/topic/28227/installing-on-windows-wizard-pages-service-account-profile-and-the-first-hour): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is the release to install today, a security release: a new server runs hMailServer-6.3.7-x64.exe, Authenticode-signed and with its Sigstore bundle beside it, and a server on 6.3.4,… Markdown: https://www.hmailserver.co.uk/llms/topic/28227.md - [Installing on Windows: wizard pages, service account, profile and the first hour](https://www.hmailserver.co.uk/topic/28227/installing-on-windows-wizard-pages-service-account-profile-and-the-first-hour): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is the release to install today, a security release: a new server runs hMailServer-6.3.7-x64.exe, Authenticode-signed and with its Sigstore bundle beside it, and a server on 6.3.4,… Markdown: https://www.hmailserver.co.uk/llms/topic/28227.md - [Choosing a database, creating it, encrypting the link and leaving the built-in one](https://www.hmailserver.co.uk/topic/28228/choosing-a-database-creating-it-encrypting-the-link-and-leaving-the-built-in-one): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds no schema step (6108, as 6.3.6). Markdown: https://www.hmailserver.co.uk/llms/topic/28228.md - [Choosing a database, creating it, encrypting the link and leaving the built-in one](https://www.hmailserver.co.uk/topic/28228/choosing-a-database-creating-it-encrypting-the-link-and-leaving-the-built-in-one): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds no schema step (6108, as 6.3.6). Markdown: https://www.hmailserver.co.uk/llms/topic/28228.md - [Your first domain and mailbox, and the DNS records your domain needs](https://www.hmailserver.co.uk/topic/28229/your-first-domain-and-mailbox-and-the-dns-records-your-domain-needs): This topic takes a freshly installed hMailServer 6.3.4 to its first working mailbox, proves it locally, and then lists the DNS records without which its mail either does not arrive or is filed as spam. The one thing to know first: the… Markdown: https://www.hmailserver.co.uk/llms/topic/28229.md - [Your first domain and mailbox, and the DNS records your domain needs](https://www.hmailserver.co.uk/topic/28229/your-first-domain-and-mailbox-and-the-dns-records-your-domain-needs): This topic takes a freshly installed hMailServer 6.3.4 to its first working mailbox, proves it locally, and then lists the DNS records without which its mail either does not arrive or is filed as spam. The one thing to know first: the… Markdown: https://www.hmailserver.co.uk/llms/topic/28229.md - [Bringing mailboxes in: IMAP mirror, Google, Microsoft 365, mbox, Maildir and PST](https://www.hmailserver.co.uk/topic/28230/bringing-mailboxes-in-imap-mirror-google-microsoft-365-mbox-maildir-and-pst): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) has the migrations as a card on the Control Panel's Backup, restore & migration page, where this topic says there is no Control Panel page; and a message collected from an external… Markdown: https://www.hmailserver.co.uk/llms/topic/28230.md - [Bringing mailboxes in: IMAP mirror, Google, Microsoft 365, mbox, Maildir and PST](https://www.hmailserver.co.uk/topic/28230/bringing-mailboxes-in-imap-mirror-google-microsoft-365-mbox-maildir-and-pst): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) has the migrations as a card on the Control Panel's Backup, restore & migration page, where this topic says there is no Control Panel page; and a message collected from an external… Markdown: https://www.hmailserver.co.uk/llms/topic/28230.md - [Unattended installs, winget and Chocolatey, and configuration from the environment](https://www.hmailserver.co.uk/topic/28231/unattended-installs-winget-and-chocolatey-and-configuration-from-the-environment): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) publishes the first container image, registry.gitlab.com/hmailserver/hmailserver:6.3.6; its installer exits 10 or 11 when a step after its files did not complete (it exited 0), and it… Markdown: https://www.hmailserver.co.uk/llms/topic/28231.md - [Unattended installs, winget and Chocolatey, and configuration from the environment](https://www.hmailserver.co.uk/topic/28231/unattended-installs-winget-and-chocolatey-and-configuration-from-the-environment): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) publishes the first container image, registry.gitlab.com/hmailserver/hmailserver:6.3.6; its installer exits 10 or 11 when a step after its files did not complete (it exited 0), and it… Markdown: https://www.hmailserver.co.uk/llms/topic/28231.md - [Warm standby and high availability: what a second machine can and cannot do](https://www.hmailserver.co.uk/topic/28232/warm-standby-and-high-availability-what-a-second-machine-can-and-cannot-do): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds no schema step, so a 6.3.6 node and a 6.3.7 node both require schema 6108 and the version check at start does not tell them apart: upgrade both nodes all the same. Markdown: https://www.hmailserver.co.uk/llms/topic/28232.md - [Warm standby and high availability: what a second machine can and cannot do](https://www.hmailserver.co.uk/topic/28232/warm-standby-and-high-availability-what-a-second-machine-can-and-cannot-do): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds no schema step, so a 6.3.6 node and a 6.3.7 node both require schema 6108 and the version check at start does not tell them apart: upgrade both nodes all the same. Markdown: https://www.hmailserver.co.uk/llms/topic/28232.md - [Message storage: compression, de-duplication, object storage and encryption at rest](https://www.hmailserver.co.uk/topic/28233/message-storage-compression-de-duplication-object-storage-and-encryption-at-rest): This topic covers the three things 6.3.4 can do to a stored message that 6.3.3 could not: store it compressed with its large attachments held once, keep it in an S3-compatible or Azure Blob store instead of under the data directory, and… Markdown: https://www.hmailserver.co.uk/llms/topic/28233.md - [Message storage: compression, de-duplication, object storage and encryption at rest](https://www.hmailserver.co.uk/topic/28233/message-storage-compression-de-duplication-object-storage-and-encryption-at-rest): This topic covers the three things 6.3.4 can do to a stored message that 6.3.3 could not: store it compressed with its large attachments held once, keep it in an S3-compatible or Azure Blob store instead of under the data directory, and… Markdown: https://www.hmailserver.co.uk/llms/topic/28233.md - [The update check and the live update: feed, verification, window and rollback](https://www.hmailserver.co.uk/topic/28234/the-update-check-and-the-live-update-feed-verification-window-and-rollback): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) is signed by the GitLab pipeline at the group path and installs by the live update from 6.3.4 or 6.3.5; from 6.3.6 the Control Panel installs an update with one click where the service… Markdown: https://www.hmailserver.co.uk/llms/topic/28234.md - [The update check and the live update: feed, verification, window and rollback](https://www.hmailserver.co.uk/topic/28234/the-update-check-and-the-live-update-feed-verification-window-and-rollback): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) is signed by the GitLab pipeline at the group path and installs by the live update from 6.3.4 or 6.3.5; from 6.3.6 the Control Panel installs an update with one click where the service… Markdown: https://www.hmailserver.co.uk/llms/topic/28234.md - [Upgrading from 5.x, 6.2 or 6.3: the 24 changes without a switch, and rolling back](https://www.hmailserver.co.uk/topic/28235/upgrading-from-5.x-6.2-or-6.3-the-24-changes-without-a-switch-and-rolling-back): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) adds three one-way schema steps (6106 to 6108), changes more without a switch (DANE lookups that do not come back whole, external accounts' days to keep messages, the COM helpers,… Markdown: https://www.hmailserver.co.uk/llms/topic/28235.md - [Upgrading from 5.x, 6.2 or 6.3: the 24 changes without a switch, and rolling back](https://www.hmailserver.co.uk/topic/28235/upgrading-from-5.x-6.2-or-6.3-the-24-changes-without-a-switch-and-rolling-back): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) adds three one-way schema steps (6106 to 6108), changes more without a switch (DANE lookups that do not come back whole, external accounts' days to keep messages, the COM helpers,… Markdown: https://www.hmailserver.co.uk/llms/topic/28235.md - [Quotas, retention and the archive: how much mail the server keeps, and for how long](https://www.hmailserver.co.uk/topic/28236/quotas-retention-and-the-archive-how-much-mail-the-server-keeps-and-for-how-long): This topic covers how much mail an hMailServer 6.3.4 server keeps, and for how long: each mailbox's limit and the quota policy 6.3.4 adds around it; retention, the administrator's and each person's, with the recover-deleted window; and… Markdown: https://www.hmailserver.co.uk/llms/topic/28236.md - [Quotas, retention and the archive: how much mail the server keeps, and for how long](https://www.hmailserver.co.uk/topic/28236/quotas-retention-and-the-archive-how-much-mail-the-server-keeps-and-for-how-long): This topic covers how much mail an hMailServer 6.3.4 server keeps, and for how long: each mailbox's limit and the quota policy 6.3.4 adds around it; retention, the administrator's and each person's, with the recover-deleted window; and… Markdown: https://www.hmailserver.co.uk/llms/topic/28236.md - [Administrator roles end to end: the 27 permissions, giving a role, where each works](https://www.hmailserver.co.uk/topic/28237/administrator-roles-end-to-end-the-27-permissions-giving-a-role-where-each-works): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that closes gaps in what this guide describes. Markdown: https://www.hmailserver.co.uk/llms/topic/28237.md - [Administrator roles end to end: the 27 permissions, giving a role, where each works](https://www.hmailserver.co.uk/topic/28237/administrator-roles-end-to-end-the-27-permissions-giving-a-role-where-each-works): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that closes gaps in what this guide describes. Markdown: https://www.hmailserver.co.uk/llms/topic/28237.md - [How the service is built and what runs out first: pools, connections, large folders](https://www.hmailserver.co.uk/topic/28238/how-the-service-is-built-and-what-runs-out-first-pools-connections-large-folders): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes three things this guide touches. Markdown: https://www.hmailserver.co.uk/llms/topic/28238.md - [How the service is built and what runs out first: pools, connections, large folders](https://www.hmailserver.co.uk/topic/28238/how-the-service-is-built-and-what-runs-out-first-pools-connections-large-folders): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes three things this guide touches. Markdown: https://www.hmailserver.co.uk/llms/topic/28238.md - [IP ranges, auto-ban, lockout, tarpits, sending limits, send-as and password storage](https://www.hmailserver.co.uk/topic/28239/ip-ranges-auto-ban-lockout-tarpits-sending-limits-send-as-and-password-storage): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that bears on the send-as and sign-in sections here. Markdown: https://www.hmailserver.co.uk/llms/topic/28239.md - [IP ranges, auto-ban, lockout, tarpits, sending limits, send-as and password storage](https://www.hmailserver.co.uk/topic/28239/ip-ranges-auto-ban-lockout-tarpits-sending-limits-send-as-and-password-storage): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that bears on the send-as and sign-in sections here. Markdown: https://www.hmailserver.co.uk/llms/topic/28239.md - [Behind a gateway, load balancer or reverse proxy: relays, PROXY, XCLIENT and HTTPS](https://www.hmailserver.co.uk/topic/28240/behind-a-gateway-load-balancer-or-reverse-proxy-relays-proxy-xclient-and-https): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds the PROXY protocol to the IMAP and POP3 listeners: each takes the client's address from a PROXY header as the SMTP listener does, from the peers on a list of its own, and both… Markdown: https://www.hmailserver.co.uk/llms/topic/28240.md - [Behind a gateway, load balancer or reverse proxy: relays, PROXY, XCLIENT and HTTPS](https://www.hmailserver.co.uk/topic/28240/behind-a-gateway-load-balancer-or-reverse-proxy-relays-proxy-xclient-and-https): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) adds the PROXY protocol to the IMAP and POP3 listeners: each takes the client's address from a PROXY header as the SMTP listener does, from the peers on a list of its own, and both… Markdown: https://www.hmailserver.co.uk/llms/topic/28240.md - [Hardening a public mail server: secure defaults, checklist, sealed secrets and roles](https://www.hmailserver.co.uk/topic/28241/hardening-a-public-mail-server-secure-defaults-checklist-sealed-secrets-and-roles): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that bears on this guide. Markdown: https://www.hmailserver.co.uk/llms/topic/28241.md - [Hardening a public mail server: secure defaults, checklist, sealed secrets and roles](https://www.hmailserver.co.uk/topic/28241/hardening-a-public-mail-server-secure-defaults-checklist-sealed-secrets-and-roles): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) is a security release that bears on this guide. Markdown: https://www.hmailserver.co.uk/llms/topic/28241.md - [Compliance: eDiscovery, legal holds, personal data, erasure and the audit trail](https://www.hmailserver.co.uk/topic/28242/compliance-ediscovery-legal-holds-personal-data-erasure-and-the-audit-trail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) regroups the Control Panel's sidebar: the audit trail, journaling and eDiscovery are a Compliance group of their own rather than the last rows of Monitoring & troubleshooting, as the… Markdown: https://www.hmailserver.co.uk/llms/topic/28242.md - [Compliance: eDiscovery, legal holds, personal data, erasure and the audit trail](https://www.hmailserver.co.uk/topic/28242/compliance-ediscovery-legal-holds-personal-data-erasure-and-the-audit-trail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) regroups the Control Panel's sidebar: the audit trail, journaling and eDiscovery are a Compliance group of their own rather than the last rows of Monitoring & troubleshooting, as the… Markdown: https://www.hmailserver.co.uk/llms/topic/28242.md - [How email works, and what hMailServer is and is not](https://www.hmailserver.co.uk/topic/28243/how-email-works-and-what-hmailserver-is-and-is-not): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries Linux packages for x86-64 and AArch64 and one for each of ten distribution releases, both AppImages, an ARM64 Windows installer (a preview) and the first container image. Markdown: https://www.hmailserver.co.uk/llms/topic/28243.md - [How email works, and what hMailServer is and is not](https://www.hmailserver.co.uk/topic/28243/how-email-works-and-what-hmailserver-is-and-is-not): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries Linux packages for x86-64 and AArch64 and one for each of ten distribution releases, both AppImages, an ARM64 Windows installer (a preview) and the first container image. Markdown: https://www.hmailserver.co.uk/llms/topic/28243.md - [Relocating an installation to another drive, and moving or renaming a mailbox](https://www.hmailserver.co.uk/topic/28244/relocating-an-installation-to-another-drive-and-moving-or-renaming-a-mailbox): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) bears on relocating a Windows installation to another drive. Markdown: https://www.hmailserver.co.uk/llms/topic/28244.md - [Relocating an installation to another drive, and moving or renaming a mailbox](https://www.hmailserver.co.uk/topic/28244/relocating-an-installation-to-another-drive-and-moving-or-renaming-a-mailbox): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) bears on relocating a Windows installation to another drive. Markdown: https://www.hmailserver.co.uk/llms/topic/28244.md - [The hmailserver command line on Linux: every verb, who runs it, the files, the unit](https://www.hmailserver.co.uk/topic/28245/the-hmailserver-command-line-on-linux-every-verb-who-runs-it-the-files-the-unit): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries .deb and .rpm packages for x86-64 and AArch64, one for each of Debian 12 and 13, Ubuntu 24.04, Fedora 43 and 44, Enterprise Linux 9 and 10, and openSUSE Leap 16.0 and… Markdown: https://www.hmailserver.co.uk/llms/topic/28245.md - [The hmailserver command line on Linux: every verb, who runs it, the files, the unit](https://www.hmailserver.co.uk/topic/28245/the-hmailserver-command-line-on-linux-every-verb-who-runs-it-the-files-the-unit): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries .deb and .rpm packages for x86-64 and AArch64, one for each of Debian 12 and 13, Ubuntu 24.04, Fedora 43 and 44, Enterprise Linux 9 and 10, and openSUSE Leap 16.0 and… Markdown: https://www.hmailserver.co.uk/llms/topic/28245.md - [In a container or on Kubernetes: the image, Compose, Helm and the environment](https://www.hmailserver.co.uk/topic/28246/in-a-container-or-on-kubernetes-the-image-compose-helm-and-the-environment): Written at 6.3.4, when no image was published. hMailServer 6.3.6 (6 October 2026) publishes the first: registry.gitlab.com/hmailserver/hmailserver:6.3.6, also tagged 6.3 and latest, one index over linux/amd64 and linux/arm64, signed with… Markdown: https://www.hmailserver.co.uk/llms/topic/28246.md - [In a container or on Kubernetes: the image, Compose, Helm and the environment](https://www.hmailserver.co.uk/topic/28246/in-a-container-or-on-kubernetes-the-image-compose-helm-and-the-environment): Written at 6.3.4, when no image was published. hMailServer 6.3.6 (6 October 2026) publishes the first: registry.gitlab.com/hmailserver/hmailserver:6.3.6, also tagged 6.3 and latest, one index over linux/amd64 and linux/arm64, signed with… Markdown: https://www.hmailserver.co.uk/llms/topic/28246.md - [Databases on Linux: PostgreSQL or MariaDB, the client, TLS and the upgrade floor](https://www.hmailserver.co.uk/topic/28247/databases-on-linux-postgresql-or-mariadb-the-client-tls-and-the-upgrade-floor): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026), a security release, keeps the schema at 6108: an upgrade from 6.3.6 changes no table, from 6.3.5 or older the upgrade runs 6.3.6's three one-way steps to 6108, and from 6.3.3 or… Markdown: https://www.hmailserver.co.uk/llms/topic/28247.md - [Databases on Linux: PostgreSQL or MariaDB, the client, TLS and the upgrade floor](https://www.hmailserver.co.uk/topic/28247/databases-on-linux-postgresql-or-mariadb-the-client-tls-and-the-upgrade-floor): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026), a security release, keeps the schema at 6108: an upgrade from 6.3.6 changes no table, from 6.3.5 or older the upgrade runs 6.3.6's three one-way steps to 6108, and from 6.3.3 or… Markdown: https://www.hmailserver.co.uk/llms/topic/28247.md - [The anti-spam stack end to end: score, greylisting, SPF, DKIM, DMARC, DNSBL, SURBL](https://www.hmailserver.co.uk/topic/28248/the-anti-spam-stack-end-to-end-score-greylisting-spf-dkim-dmarc-dnsbl-surbl): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) reads a DNS lookup that fails as a failure, not as a name with no addresses: the HELO and PTR tests no longer score a name they could not look up, a DNS blacklist and SURBL no longer… Markdown: https://www.hmailserver.co.uk/llms/topic/28248.md - [The anti-spam stack end to end: score, greylisting, SPF, DKIM, DMARC, DNSBL, SURBL](https://www.hmailserver.co.uk/topic/28248/the-anti-spam-stack-end-to-end-score-greylisting-spf-dkim-dmarc-dnsbl-surbl): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) reads a DNS lookup that fails as a failure, not as a name with no addresses: the HELO and PTR tests no longer score a name they could not look up, a DNS blacklist and SURBL no longer… Markdown: https://www.hmailserver.co.uk/llms/topic/28248.md - [Allow and block lists, digests, spam traps, country blocking and impersonation](https://www.hmailserver.co.uk/topic/28249/allow-and-block-lists-digests-spam-traps-country-blocking-and-impersonation): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) reads a link's host that is not ASCII by UTS 46, and an HTML part's character references as a browser does, for the URL entries of the allow and block lists, so a message whose links… Markdown: https://www.hmailserver.co.uk/llms/topic/28249.md - [Allow and block lists, digests, spam traps, country blocking and impersonation](https://www.hmailserver.co.uk/topic/28249/allow-and-block-lists-digests-spam-traps-country-blocking-and-impersonation): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) reads a link's host that is not ASCII by UTS 46, and an HTML part's character references as a browser does, for the URL entries of the allow and block lists, so a message whose links… Markdown: https://www.hmailserver.co.uk/llms/topic/28249.md - [Viruses and dangerous attachments: ClamAV, custom scanners, the sandbox, sealed mail](https://www.hmailserver.co.uk/topic/28250/viruses-and-dangerous-attachments-clamav-custom-scanners-the-sandbox-sealed-mail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) calls the anti-virus action that strips attachments Remove all attachments and deliver the text (Delete infected attachments only in 6.3.6's Control Panel), and under it a message… Markdown: https://www.hmailserver.co.uk/llms/topic/28250.md - [Viruses and dangerous attachments: ClamAV, custom scanners, the sandbox, sealed mail](https://www.hmailserver.co.uk/topic/28250/viruses-and-dangerous-attachments-clamav-custom-scanners-the-sandbox-sealed-mail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) calls the anti-virus action that strips attachments Remove all attachments and deliver the text (Delete infected attachments only in 6.3.6's Control Panel), and under it a message… Markdown: https://www.hmailserver.co.uk/llms/topic/28250.md - [Mail flow rules, the outbound content policy and what a domain does to a message](https://www.hmailserver.co.uk/topic/28251/mail-flow-rules-the-outbound-content-policy-and-what-a-domain-does-to-a-message): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a domain's or an account's rule to its owner: it may no longer set From, Sender, Resent-From, Resent-Sender, DKIM-Signature or the loop count, and its Reply goes only from an… Markdown: https://www.hmailserver.co.uk/llms/topic/28251.md - [Mail flow rules, the outbound content policy and what a domain does to a message](https://www.hmailserver.co.uk/topic/28251/mail-flow-rules-the-outbound-content-policy-and-what-a-domain-does-to-a-message): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a domain's or an account's rule to its owner: it may no longer set From, Sender, Resent-From, Resent-Sender, DKIM-Signature or the loop count, and its Reply goes only from an… Markdown: https://www.hmailserver.co.uk/llms/topic/28251.md - [Calendars, contacts, the directory and shared address books over CalDAV and CardDAV](https://www.hmailserver.co.uk/topic/28252/calendars-contacts-the-directory-and-shared-address-books-over-caldav-and-carddav): This topic covers what hMailServer 6.3.4 serves to a phone or a desktop client over CalDAV and CardDAV, and what the webmail's Calendar, Tasks, Contacts and Directory pages do with the same data. The one thing to know first: CalDAV and… Markdown: https://www.hmailserver.co.uk/llms/topic/28252.md - [Calendars, contacts, the directory and shared address books over CalDAV and CardDAV](https://www.hmailserver.co.uk/topic/28252/calendars-contacts-the-directory-and-shared-address-books-over-caldav-and-carddav): This topic covers what hMailServer 6.3.4 serves to a phone or a desktop client over CalDAV and CardDAV, and what the webmail's Calendar, Tasks, Contacts and Directory pages do with the same data. The one thing to know first: CalDAV and… Markdown: https://www.hmailserver.co.uk/llms/topic/28252.md - [Signing in: passwords, second factor, passkeys, single sign-on, recovery, devices](https://www.hmailserver.co.uk/topic/28253/signing-in-passwords-second-factor-passkeys-single-sign-on-recovery-devices): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a state-changing REST request that carries a credential - HTTP Basic included, which a browser keeps once it has answered the sign-in box - when the browser reports it as… Markdown: https://www.hmailserver.co.uk/llms/topic/28253.md - [Signing in: passwords, second factor, passkeys, single sign-on, recovery, devices](https://www.hmailserver.co.uk/topic/28253/signing-in-passwords-second-factor-passkeys-single-sign-on-recovery-devices): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a state-changing REST request that carries a credential - HTTP Basic included, which a browser keeps once it has answered the sign-in box - when the browser reports it as… Markdown: https://www.hmailserver.co.uk/llms/topic/28253.md - [The webmail in depth: search, offline mail, expiring messages, send-as and recovery](https://www.hmailserver.co.uk/topic/28254/the-webmail-in-depth-search-offline-mail-expiring-messages-send-as-and-recovery): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) signs an authenticated SMTP submission as another domain hosted here only when its account may send as the address its From names - the list the From picker below draws on: its own… Markdown: https://www.hmailserver.co.uk/llms/topic/28254.md - [The webmail in depth: search, offline mail, expiring messages, send-as and recovery](https://www.hmailserver.co.uk/topic/28254/the-webmail-in-depth-search-offline-mail-expiring-messages-send-as-and-recovery): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) signs an authenticated SMTP submission as another domain hosted here only when its account may send as the address its From names - the list the From picker below draws on: its own… Markdown: https://www.hmailserver.co.uk/llms/topic/28254.md - [Connecting a mail client: IMAP, POP3, SMTP submission, app passwords and the ports](https://www.hmailserver.co.uk/topic/28255/connecting-a-mail-client-imap-pop3-smtp-submission-app-passwords-and-the-ports): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) accepts the UTF8 that classic Outlook for Windows (Outlook 2016 to 2024) sends after the POP3 login, at which its downloads had stopped; SMTP, POP3 and ManageSieve refuse a SASL PLAIN… Markdown: https://www.hmailserver.co.uk/llms/topic/28255.md - [Connecting a mail client: IMAP, POP3, SMTP submission, app passwords and the ports](https://www.hmailserver.co.uk/topic/28255/connecting-a-mail-client-imap-pop3-smtp-submission-app-passwords-and-the-ports): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) accepts the UTF8 that classic Outlook for Windows (Outlook 2016 to 2024) sends after the POP3 login, at which its downloads had stopped; SMTP, POP3 and ManageSieve refuse a SASL PLAIN… Markdown: https://www.hmailserver.co.uk/llms/topic/28255.md - [TLS on the listeners: your own certificate, versions, ciphers and client certificates](https://www.hmailserver.co.uk/topic/28256/tls-on-the-listeners-your-own-certificate-versions-ciphers-and-client-certificates): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) renames two Control Panel pages this topic names: SSL certificates is TLS certificates and SSL/TLS is TLS versions & ciphers; Ctrl+K takes every old title and route to its page. Markdown: https://www.hmailserver.co.uk/llms/topic/28256.md - [TLS on the listeners: your own certificate, versions, ciphers and client certificates](https://www.hmailserver.co.uk/topic/28256/tls-on-the-listeners-your-own-certificate-versions-ciphers-and-client-certificates): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) renames two Control Panel pages this topic names: SSL certificates is TLS certificates and SSL/TLS is TLS versions & ciphers; Ctrl+K takes every old title and route to its page. Markdown: https://www.hmailserver.co.uk/llms/topic/28256.md - [Requiring TLS: MTA-STS and TLS-RPT, DANE with ACME, and remote domain policies](https://www.hmailserver.co.uk/topic/28257/requiring-tls-mta-sts-and-tls-rpt-dane-with-acme-and-remote-domain-policies): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) fixes DANE enforcement deferring mail to a DNSSEC-signed domain whose MX answer came compressed, live.com among them (work item 80), and treats a DNS lookup that fails as a failure… Markdown: https://www.hmailserver.co.uk/llms/topic/28257.md - [Requiring TLS: MTA-STS and TLS-RPT, DANE with ACME, and remote domain policies](https://www.hmailserver.co.uk/topic/28257/requiring-tls-mta-sts-and-tls-rpt-dane-with-acme-and-remote-domain-policies): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) fixes DANE enforcement deferring mail to a DNSSEC-signed domain whose MX answer came compressed, live.com among them (work item 80), and treats a DNS lookup that fails as a failure… Markdown: https://www.hmailserver.co.uk/llms/topic/28257.md - [DKIM rotation, DMARC and TLS reports, complaints, bounces and the reputation watch](https://www.hmailserver.co.uk/topic/28258/dkim-rotation-dmarc-and-tls-reports-complaints-bounces-and-the-reputation-watch): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) no longer signs mail from outside whose From names a domain hosted here with that domain's DKIM key, and signs an authenticated submission as another hosted domain only when its… Markdown: https://www.hmailserver.co.uk/llms/topic/28258.md - [DKIM rotation, DMARC and TLS reports, complaints, bounces and the reputation watch](https://www.hmailserver.co.uk/topic/28258/dkim-rotation-dmarc-and-tls-reports-complaints-bounces-and-the-reputation-watch): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) no longer signs mail from outside whose From names a domain hosted here with that domain's DKIM key, and signs an authenticated submission as another hosted domain only when its… Markdown: https://www.hmailserver.co.uk/llms/topic/28258.md - [Outbound shaping and IP warm-up: one slow destination must not stall the queue](https://www.hmailserver.co.uk/topic/28259/outbound-shaping-and-ip-warm-up-one-slow-destination-must-not-stall-the-queue): Since 6.3.4 the delivery queue shapes what it sends. It pauses a destination that asked it to slow down, caps how many sessions it holds open to one destination and how many deliveries one tenant has in flight, and holds a new outbound… Markdown: https://www.hmailserver.co.uk/llms/topic/28259.md - [Outbound shaping and IP warm-up: one slow destination must not stall the queue](https://www.hmailserver.co.uk/topic/28259/outbound-shaping-and-ip-warm-up-one-slow-destination-must-not-stall-the-queue): Since 6.3.4 the delivery queue shapes what it sends. It pauses a destination that asked it to slow down, caps how many sessions it holds open to one destination and how many deliveries one tenant has in flight, and holds a new outbound… Markdown: https://www.hmailserver.co.uk/llms/topic/28259.md - [End-to-end encryption: S/MIME authority, OpenPGP and WKD, zero access, sealed mail](https://www.hmailserver.co.uk/topic/28260/end-to-end-encryption-s-mime-authority-openpgp-and-wkd-zero-access-sealed-mail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes the anti-virus action that removes attachments (Remove all attachments and deliver the text in 6.3.7's Control Panel, Delete infected attachments only in 6.3.6's): an S/MIME… Markdown: https://www.hmailserver.co.uk/llms/topic/28260.md - [End-to-end encryption: S/MIME authority, OpenPGP and WKD, zero access, sealed mail](https://www.hmailserver.co.uk/topic/28260/end-to-end-encryption-s-mime-authority-openpgp-and-wkd-zero-access-sealed-mail): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes the anti-virus action that removes attachments (Remove all attachments and deliver the text in 6.3.7's Control Panel, Delete infected attachments only in 6.3.6's): an S/MIME… Markdown: https://www.hmailserver.co.uk/llms/topic/28260.md - [Event scripts: every event and its arguments, the limits, and the 6.3.4 security fix](https://www.hmailserver.co.uk/topic/28261/event-scripts-every-event-and-its-arguments-the-limits-and-the-6.3.4-security-fix): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a rule's Run function action when the rule is saved unless it names a plain function, for a rule of every owner, over COM and REST, and setting one on a domain's or an… Markdown: https://www.hmailserver.co.uk/llms/topic/28261.md - [Event scripts: every event and its arguments, the limits, and the 6.3.4 security fix](https://www.hmailserver.co.uk/topic/28261/event-scripts-every-event-and-its-arguments-the-limits-and-the-6.3.4-security-fix): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a rule's Run function action when the rule is saved unless it names a plain function, for a rule of every owner, over COM and REST, and setting one on a domain's or an… Markdown: https://www.hmailserver.co.uk/llms/topic/28261.md - [The COM API on Windows: object model, Save() since 6.3.4, roles and the Import Tool](https://www.hmailserver.co.uk/topic/28262/the-com-api-on-windows-object-model-save-since-6.3.4-roles-and-the-import-tool): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) confines an account given the serveradmin role with a list of domains to those domains over COM as over REST, so it is no longer the server's administrator: give the role with no list… Markdown: https://www.hmailserver.co.uk/llms/topic/28262.md - [The COM API on Windows: object model, Save() since 6.3.4, roles and the Import Tool](https://www.hmailserver.co.uk/topic/28262/the-com-api-on-windows-object-model-save-since-6.3.4-roles-and-the-import-tool): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) confines an account given the serveradmin role with a list of domains to those domains over COM as over REST, so it is no longer the server's administrator: give the role with no list… Markdown: https://www.hmailserver.co.uk/llms/topic/28262.md - [Active Directory and LDAP sign-in, directory synchronisation and OAuth2 bearer tokens](https://www.hmailserver.co.uk/topic/28263/active-directory-and-ldap-sign-in-directory-synchronisation-and-oauth2-bearer-tokens): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes three things this guide relies on. Markdown: https://www.hmailserver.co.uk/llms/topic/28263.md - [Active Directory and LDAP sign-in, directory synchronisation and OAuth2 bearer tokens](https://www.hmailserver.co.uk/topic/28263/active-directory-and-ldap-sign-in-directory-synchronisation-and-oauth2-bearer-tokens): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes three things this guide relies on. Markdown: https://www.hmailserver.co.uk/llms/topic/28263.md - [The REST API: turning it on, credentials, roles, one-time codes, OpenAPI and examples](https://www.hmailserver.co.uk/topic/28264/the-rest-api-turning-it-on-credentials-roles-one-time-codes-openapi-and-examples): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes how the listener judges some requests. Markdown: https://www.hmailserver.co.uk/llms/topic/28264.md - [The REST API: turning it on, credentials, roles, one-time codes, OpenAPI and examples](https://www.hmailserver.co.uk/topic/28264/the-rest-api-turning-it-on-credentials-roles-one-time-codes-openapi-and-examples): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) changes how the listener judges some requests. Markdown: https://www.hmailserver.co.uk/llms/topic/28264.md - [hmctl and the PowerShell module: shell administration and accounts from a CSV file](https://www.hmailserver.co.uk/topic/28265/hmctl-and-the-powershell-module-shell-administration-and-accounts-from-a-csv-file): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries the PowerShell module, HmailServer.psd1 and HmailServer.psm1, Authenticode-signed, as files of the release, and Linux packages for x86-64 and AArch64; hmctl as a PyPI package… Markdown: https://www.hmailserver.co.uk/llms/topic/28265.md - [hmctl and the PowerShell module: shell administration and accounts from a CSV file](https://www.hmailserver.co.uk/topic/28265/hmctl-and-the-powershell-module-shell-administration-and-accounts-from-a-csv-file): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) carries the PowerShell module, HmailServer.psd1 and HmailServer.psm1, Authenticode-signed, as files of the release, and Linux packages for x86-64 and AArch64; hmctl as a PyPI package… Markdown: https://www.hmailserver.co.uk/llms/topic/28265.md - [Integrating applications: the send API, mail in to a webhook, and outbound webhooks](https://www.hmailserver.co.uk/topic/28266/integrating-applications-the-send-api-mail-in-to-a-webhook-and-outbound-webhooks): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a state-changing REST request that carries a credential when the browser making it reports it as cross-site (Sec-Fetch-Site, or an Origin that is not this server's), so a page… Markdown: https://www.hmailserver.co.uk/llms/topic/28266.md - [Integrating applications: the send API, mail in to a webhook, and outbound webhooks](https://www.hmailserver.co.uk/topic/28266/integrating-applications-the-send-api-mail-in-to-a-webhook-and-outbound-webhooks): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) refuses a state-changing REST request that carries a credential when the browser making it reports it as cross-site (Sec-Fetch-Site, or an Origin that is not this server's), so a page… Markdown: https://www.hmailserver.co.uk/llms/topic/28266.md - [SCIM provisioning from Entra ID and Okta, and single sign-on for the organisation](https://www.hmailserver.co.uk/topic/28267/scim-provisioning-from-entra-id-and-okta-and-single-sign-on-for-the-organisation): An organisation that keeps its people in an identity provider wants two things of its mail server: mailboxes that follow the directory, and a sign-in that goes through it. Since 6.3.4 hMailServer has both. Markdown: https://www.hmailserver.co.uk/llms/topic/28267.md - [SCIM provisioning from Entra ID and Okta, and single sign-on for the organisation](https://www.hmailserver.co.uk/topic/28267/scim-provisioning-from-entra-id-and-okta-and-single-sign-on-for-the-organisation): An organisation that keeps its people in an identity provider wants two things of its mail server: mailboxes that follow the directory, and a sign-in that goes through it. Since 6.3.4 hMailServer has both. Markdown: https://www.hmailserver.co.uk/llms/topic/28267.md - [Rules and Sieve: what runs when, vacation replies and the Run function action](https://www.hmailserver.co.uk/topic/28268/rules-and-sieve-what-runs-when-vacation-replies-and-the-run-function-action): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a rule and a Sieve script to their owner: a domain's or an account's rule may no longer set From, Sender, Resent-From, Resent-Sender, DKIM-Signature or the loop count, and its… Markdown: https://www.hmailserver.co.uk/llms/topic/28268.md - [Rules and Sieve: what runs when, vacation replies and the Run function action](https://www.hmailserver.co.uk/topic/28268/rules-and-sieve-what-runs-when-vacation-replies-and-the-run-function-action): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a rule and a Sieve script to their owner: a domain's or an account's rule may no longer set From, Sender, Resent-From, Resent-Sender, DKIM-Signature or the loop count, and its… Markdown: https://www.hmailserver.co.uk/llms/topic/28268.md - [Routes, relays and smart hosts, OAuth2 relaying, restricted delivery and recall](https://www.hmailserver.co.uk/topic/28269/routes-relays-and-smart-hosts-oauth2-relaying-restricted-delivery-and-recall): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a credential confined to named domains - such as a domain administrator, or an API key issued for its domains - to a public address when it changes a domain's relay host, so it… Markdown: https://www.hmailserver.co.uk/llms/topic/28269.md - [Routes, relays and smart hosts, OAuth2 relaying, restricted delivery and recall](https://www.hmailserver.co.uk/topic/28269/routes-relays-and-smart-hosts-oauth2-relaying-restricted-delivery-and-recall): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) holds a credential confined to named domains - such as a domain administrator, or an API key issued for its domains - to a public address when it changes a domain's relay host, so it… Markdown: https://www.hmailserver.co.uk/llms/topic/28269.md - [Aliases, distribution lists, membership queries, mailing lists and public folders](https://www.hmailserver.co.uk/topic/28270/aliases-distribution-lists-membership-queries-mailing-lists-and-public-folders): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) signs an authenticated submission as another hosted domain only when the account may send as the address its From names - its own, an alias pointing at it, a mailbox that granted it… Markdown: https://www.hmailserver.co.uk/llms/topic/28270.md - [Aliases, distribution lists, membership queries, mailing lists and public folders](https://www.hmailserver.co.uk/topic/28270/aliases-distribution-lists-membership-queries-mailing-lists-and-public-folders): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) signs an authenticated submission as another hosted domain only when the account may send as the address its From names - its own, an alias pointing at it, a mailbox that granted it… Markdown: https://www.hmailserver.co.uk/llms/topic/28270.md - [Journaling and dual delivery: a compliance copy, and what a journal rule does not see](https://www.hmailserver.co.uk/topic/28271/journaling-and-dual-delivery-a-compliance-copy-and-what-a-journal-rule-does-not-see): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) regroups the Control Panel's sidebar: the Journaling and dual delivery page is Journaling & dual delivery, in the new Compliance group rather than under Monitoring & troubleshooting… Markdown: https://www.hmailserver.co.uk/llms/topic/28271.md - [Journaling and dual delivery: a compliance copy, and what a journal rule does not see](https://www.hmailserver.co.uk/topic/28271/journaling-and-dual-delivery-a-compliance-copy-and-what-a-journal-rule-does-not-see): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) regroups the Control Panel's sidebar: the Journaling and dual delivery page is Journaling & dual delivery, in the new Compliance group rather than under Monitoring & troubleshooting… Markdown: https://www.hmailserver.co.uk/llms/topic/28271.md - [Monitoring and health: Prometheus metrics, health probes, Grafana, OTLP and SNMPv3](https://www.hmailserver.co.uk/topic/28272/monitoring-and-health-prometheus-metrics-health-probes-grafana-otlp-and-snmpv3): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) publishes the first container image, registry.gitlab.com/hmailserver/hmailserver:6.3.6, and a monitor that matches "The response carried no HTTP headers." needs the new sentence, which… Markdown: https://www.hmailserver.co.uk/llms/topic/28272.md - [Monitoring and health: Prometheus metrics, health probes, Grafana, OTLP and SNMPv3](https://www.hmailserver.co.uk/topic/28272/monitoring-and-health-prometheus-metrics-health-probes-grafana-otlp-and-snmpv3): Written for 6.3.4. hMailServer 6.3.6 (6 October 2026) publishes the first container image, registry.gitlab.com/hmailserver/hmailserver:6.3.6, and a monitor that matches "The response carried no HTTP headers." needs the new sentence, which… Markdown: https://www.hmailserver.co.uk/llms/topic/28272.md - [Alerts, the audit trail, syslog and the journal, and per-domain reports](https://www.hmailserver.co.uk/topic/28273/alerts-the-audit-trail-syslog-and-the-journal-and-per-domain-reports): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) moves the Control Panel's Audit trail page, with journaling and eDiscovery, into a new Compliance group, and the alerts' settings, the outbound webhooks and the SNMP agent onto its… Markdown: https://www.hmailserver.co.uk/llms/topic/28273.md - [Alerts, the audit trail, syslog and the journal, and per-domain reports](https://www.hmailserver.co.uk/topic/28273/alerts-the-audit-trail-syslog-and-the-journal-and-per-domain-reports): Written for 6.3.4. hMailServer 6.3.7 (17 October 2026) moves the Control Panel's Audit trail page, with journaling and eDiscovery, into a new Compliance group, and the alerts' settings, the outbound webhooks and the SNMP agent onto its… Markdown: https://www.hmailserver.co.uk/llms/topic/28273.md - [Documentation index: every guide on this forum, by subject](https://www.hmailserver.co.uk/topic/28274/documentation-index-every-guide-on-this-forum-by-subject): Every documentation topic on this forum, by the category it sits in. Each one is written from the project's wiki and the operator documents at the release tag, for hMailServer 6.3.4, and links the pages it was written from. Markdown: https://www.hmailserver.co.uk/llms/topic/28274.md ## Releases, newest first - [hMailServer 6.3.7](https://www.hmailserver.co.uk/topic/28277/hmailserver-6.3.7-security-fixes-for-every-earlier-version-read-before-upgrading-and-the-first-security-release-of-the-pause) (17 October 2026): security fixes for every earlier version, read before upgrading, and the first security release of the pause - [hMailServer 6.3.6](https://www.hmailserver.co.uk/topic/28276/hmailserver-6.3.6-security-fixes-for-every-earlier-version-read-before-upgrading-and-the-last-release-for-the-time-being) (6 October 2026): security fixes for every earlier version, read before upgrading, and the last release for the time being - [hMailServer 6.3.5](https://www.hmailserver.co.uk/topic/28275/hmailserver-6.3.5-the-first-release-built-and-signed-by-its-gitlab-pipeline-and-the-quarantine-grouped-by-domain-and-helo) (29 September 2026): the first release built and signed by its GitLab pipeline, and the quarantine grouped by domain and HELO - [hMailServer 6.3.4](https://www.hmailserver.co.uk/topic/28218/hmailserver-6.3.4-a-password-could-run-code-on-windows-servers-with-jscript-scripting) (27 September 2026): a password could run code on Windows servers with JScript scripting - [hMailServer 6.3.3](https://www.hmailserver.co.uk/topic/28183/hmailserver-6.3.3-outbound-bdat-stalled-every-message-over-60-000-bytes) (15 September 2026): outbound BDAT stalled every message over 60,000 bytes - [hMailServer 6.3.2](https://www.hmailserver.co.uk/topic/28180/hmailserver-6.3.2-a-public-resolver-made-surbl-tag-every-message-with-a-link-as-spam) (13 September 2026): a public resolver made SURBL tag every message with a link as spam - [hMailServer 6.3.1](https://www.hmailserver.co.uk/topic/28179/hmailserver-6.3.1-the-installer-is-signed-and-updaterequireauthenticode-works) (11 September 2026): the installer is signed, and UpdateRequireAuthenticode works - [hMailServer 6.3.0](https://www.hmailserver.co.uk/topic/28184/hmailserver-6.3.0-the-server-runs-on-linux-but-not-with-per-domain-dkim-signing) (10 September 2026): the server runs on Linux, but not with per-domain DKIM signing - [hMailServer 6.2.28](https://www.hmailserver.co.uk/topic/28178/hmailserver-6.2.28-the-server-can-verify-and-apply-its-own-updates) (8 September 2026): the server can verify and apply its own updates - [hMailServer 6.2.27](https://www.hmailserver.co.uk/topic/28181/hmailserver-6.2.27-a-stripped-ds-record-turned-a-signed-zone-unsigned) (7 September 2026): a stripped DS record turned a signed zone unsigned - [hMailServer 6.2.26](https://www.hmailserver.co.uk/topic/28167/hmailserver-6.2.26-sql-server-compact-upgrades-to-schema-6030-reported-as-failed) (6 September 2026): SQL Server Compact upgrades to schema 6030 reported as failed - [hMailServer 6.2.25](https://www.hmailserver.co.uk/topic/28173/hmailserver-6.2.25-acme-issuance-and-renewal-terminated-the-server-process) (6 September 2026): ACME issuance and renewal terminated the server process - [hMailServer 6.2.24](https://www.hmailserver.co.uk/topic/28170/hmailserver-6.2.24-delegated-imap-move-could-destroy-the-only-copy-of-a-message) (4 September 2026): delegated IMAP MOVE could destroy the only copy of a message - [hMailServer 6.2.21](https://www.hmailserver.co.uk/topic/28165/hmailserver-6.2.21-inbound-mail-from-a-postfix-relay-could-hang-forever) (16 August 2026): inbound mail from a Postfix relay could hang forever - [hMailServer 6.2.20](https://www.hmailserver.co.uk/topic/28169/hmailserver-6.2.20-fresh-installs-failed-and-silent-installs-hung-on-a-dialog) (15 August 2026): fresh installs failed and silent installs hung on a dialog - [hMailServer 6.2.19](https://www.hmailserver.co.uk/topic/28177/hmailserver-6.2.19-custom-dns-server-broke-every-lookup-since-6.2.16) (15 August 2026): custom DNS server broke every lookup since 6.2.16 - [hMailServer 6.2.18](https://www.hmailserver.co.uk/topic/28166/hmailserver-6.2.18-a-stalled-database-bounced-valid-mail-instead-of-retrying-it) (12 August 2026): a stalled database bounced valid mail instead of retrying it - [hMailServer 6.2.17](https://www.hmailserver.co.uk/topic/28171/hmailserver-6.2.17-relayed-mail-could-stall-after-end-of-data-with-no-250) (12 August 2026): relayed mail could stall after end-of-data with no 250 - [hMailServer 6.2.16](https://www.hmailserver.co.uk/topic/28200/hmailserver-6.2.16-an-error-dialog-on-closing-the-ctrl-k-settings-palette) (11 August 2026): an error dialog on closing the Ctrl+K settings palette - [hMailServer 6.2.15](https://www.hmailserver.co.uk/topic/28207/hmailserver-6.2.15-imap-sequence-sets-and-a-restore-that-could-empty-the-data-directory) (11 August 2026): IMAP sequence sets, and a restore that could empty the data directory - [hMailServer 6.2.14](https://www.hmailserver.co.uk/topic/28205/hmailserver-6.2.14-imap-append-reported-success-for-mail-it-never-wrote) (11 August 2026): IMAP APPEND reported success for mail it never wrote - [hMailServer 6.2.13](https://www.hmailserver.co.uk/topic/28204/hmailserver-6.2.13-a-data-stall-on-relayed-mail) (11 August 2026): a DATA stall on relayed mail - [hMailServer 6.2.12](https://www.hmailserver.co.uk/topic/28206/hmailserver-6.2.12-every-c-component-now-targets-.net-8) (10 August 2026): every C# component now targets .NET 8 - [hMailServer 6.2.11](https://www.hmailserver.co.uk/topic/28208/hmailserver-6.2.11-two-control-panel-lists-read-their-class-name-to-screen-readers) (7 August 2026): two Control Panel lists read their class name to screen readers - [hMailServer 6.2.10](https://www.hmailserver.co.uk/topic/28201/hmailserver-6.2.10-the-com-api-reported-success-on-calls-it-refused) (7 August 2026): the COM API reported success on calls it refused - [hMailServer 6.2.9](https://www.hmailserver.co.uk/topic/28198/hmailserver-6.2.9-the-dashboard-charts-that-rendered-white) (7 August 2026): the dashboard charts that rendered white - [hMailServer 6.2.8](https://www.hmailserver.co.uk/topic/28202/hmailserver-6.2.8-blank-list-editors-and-a-control-panel-that-died-on-restart) (7 August 2026): blank list editors and a Control Panel that died on restart - [hMailServer 6.2.7](https://www.hmailserver.co.uk/topic/28195/hmailserver-6.2.7-file-pickers-and-one-click-dkim-in-the-control-panel) (15 June 2026): file pickers and one-click DKIM in the Control Panel - [hMailServer 6.2.6](https://www.hmailserver.co.uk/topic/28199/hmailserver-6.2.6-imap4rev2-as-an-opt-in-mode-and-a-control-panel-redesign) (15 June 2026): IMAP4rev2 as an opt-in mode, and a Control Panel redesign - [hMailServer 6.2.5](https://www.hmailserver.co.uk/topic/28197/hmailserver-6.2.5-default-installs-could-not-connect-to-their-own-database) (15 June 2026): default installs could not connect to their own database - [hMailServer 6.2.4](https://www.hmailserver.co.uk/topic/28203/hmailserver-6.2.4-active-directory-account-pickers-in-the-control-panel) (15 June 2026): Active Directory account pickers in the Control Panel - [hMailServer 6.2.3](https://www.hmailserver.co.uk/topic/28196/hmailserver-6.2.3-sieve-and-managesieve-filtering) (15 June 2026): Sieve and ManageSieve filtering - [hMailServer 6.2.2](https://www.hmailserver.co.uk/topic/28215/hmailserver-6.2.2-rfc-4013-saslprep-and-a-substantially-upgraded-control-panel) (14 June 2026): RFC 4013 SASLprep and a substantially upgraded Control Panel - [hMailServer 6.2.1](https://www.hmailserver.co.uk/topic/28214/hmailserver-6.2.1-pipelining-smtputf8-dsn-and-srs) (14 June 2026): PIPELINING, SMTPUTF8, DSN and SRS - [hMailServer 6.2.0](https://www.hmailserver.co.uk/topic/28209/hmailserver-6.2.0-the-new-control-panel-desktop-administration-app) (14 June 2026): the new Control Panel desktop administration app - [hMailServer 6.1.0](https://www.hmailserver.co.uk/topic/28210/hmailserver-6.1.0-the-web-control-deck-and-a-light-dark-administrator) (12 June 2026): the Web Control Deck and a light/dark Administrator - [hMailServer 6.0.0](https://www.hmailserver.co.uk/topic/28213/hmailserver-6.0.0-the-modernised-baseline-and-the-build-4-installer-fix) (12 June 2026): the modernised baseline, and the build 4 installer fix ## Forum - [Forum rules](https://www.hmailserver.co.uk/rules) - [About this forum](https://www.hmailserver.co.uk/about) - [Posting a support request](https://www.hmailserver.co.uk/how-to-ask) - [Announcements & releases](https://www.hmailserver.co.uk/category/1/announcements-releases): Release notes, security advisories and forum notices from the maintainers. Read-only; questions belong in the categories below. - [General support](https://www.hmailserver.co.uk/category/8/general-support): SMTP, IMAP, POP3, accounts, queues and delivery on hMailServer 6.3 and later. Anything without a narrower home below. - [Pre-release builds](https://www.hmailserver.co.uk/category/11/pre-release-builds): Alpha, beta and release-candidate builds. Anything running in production belongs in Running hMailServer instead. - [Scripting & the COM API](https://www.hmailserver.co.uk/category/9/scripting-the-com-api): VBScript and JScript event handlers on Windows, JavaScript ones on Linux since 6.3.4, OnAcceptMessage and friends, and the COM API and the Import Tool, which are Windows only. Paste the script and the error it raised. - [Installation, migration & upgrades](https://www.hmailserver.co.uk/category/15/installation-migration-upgrades): First installs, 5.x → 6.3.7 in place, moves to new hardware, and imports from other mail servers. Say which version you are on, which you are going to, and the database. - [REST API & integrations](https://www.hmailserver.co.uk/category/20/rest-api-integrations): The REST API that RestApiPort turns on — tokens and OAuth2, provisioning scripts, and control panels, billing systems and directory syncs that call it. - [Running hMailServer](https://www.hmailserver.co.uk/category/5/running-hmailserver): Running a live mail server: installs, upgrades, Windows and Linux, TLS and DNS, spam, webmail and the Control Deck. Post in the closest child, not here. - [Automation & integration](https://www.hmailserver.co.uk/category/19/automation-integration): Driving hMailServer from outside the Control Panel: scripts, the COM and REST APIs, Sieve and rules, and metrics and logs shipped elsewhere. - [Rules, Sieve & routing](https://www.hmailserver.co.uk/category/21/rules-sieve-routing): Sieve (RFC 5228) and ManageSieve, the classic rules engine, global rules, SMTP routes, aliases and distribution lists — sorting and steering mail without code. - [Guides & tutorials](https://www.hmailserver.co.uk/category/10/guides-tutorials): Walkthroughs that worked on a real server — give the version, platform and database. The official manual stays at progressiverobot.com/hmailserver-documentation/. - [Linux](https://www.hmailserver.co.uk/category/16/linux): 6.3 on Linux: .deb and .rpm for x86-64 and AArch64, with a package for each distribution release from 6.3.6 (6.3.4 and 6.3.5 were x86-64 only), the AppImages, the container image, PKGBUILD, systemd units, /etc/hmailserver, PostgreSQL or MariaDB. No Control Panel and no COM here. - [Anti-spam & message filtering](https://www.hmailserver.co.uk/category/14/anti-spam-message-filtering): Greylisting, DNSBL and SURBL, SpamAssassin and rspamd, quarantine and false positives. Rules and Sieve recipes go in Rules, Sieve & routing instead. - [Monitoring, metrics & logs](https://www.hmailserver.co.uk/category/22/monitoring-metrics-logs): Prometheus and OTLP, /livez and /readyz, JSON logs into Elasticsearch, Loki or Splunk, and reading hMailServer's own logs when you are chasing a delivery. - [Webmail, portal & Control Deck](https://www.hmailserver.co.uk/category/17/webmail-portal-control-deck): The built-in webmail at /portal and browser administration at / — folders, compose, shared folders, calendars, CardDAV and CalDAV, passkeys and sessions. - [Development & roadmap](https://www.hmailserver.co.uk/category/6/development-roadmap): The software itself rather than your server — defects, pre-release builds and what 6.4 should do. Source and merge requests live on gitlab.com/hmailserver/hmailserver, mirrored on GitHub at github.com/RainbowWizard-coder/hMailServer. - [TLS, certificates & deliverability](https://www.hmailserver.co.uk/category/18/tls-certificates-deliverability): Let's Encrypt and ACME, TLS 1.2/1.3, MTA-STS, DANE and DNSSEC, plus SPF, DKIM, DMARC, SRS and BATV — being trusted by the servers you send to. ## Optional - [hMailServer 6.2.23-alpha2](https://www.hmailserver.co.uk/topic/28172/hmailserver-6.2.23-alpha2-thunderbird-could-not-save-a-single-sent-copy) (4 September 2026, pre-release, superseded): Thunderbird could not save a single Sent copy - [hMailServer 6.2.23-alpha1](https://www.hmailserver.co.uk/topic/28175/hmailserver-6.2.23-alpha1-local-delivery-could-lose-a-message-after-answering-250) (21 August 2026, pre-release, superseded): local delivery could lose a message after answering 250 - [hMailServer 6.2.22-pre6](https://www.hmailserver.co.uk/topic/28182/hmailserver-6.2.22-pre6-pre4-was-withdrawn-a-fresh-install-listened-on-nothing) (20 August 2026, pre-release, superseded): pre4 was withdrawn, a fresh install listened on nothing - [hMailServer 6.2.22-pre3](https://www.hmailserver.co.uk/topic/28176/hmailserver-6.2.22-pre3-the-server-now-enforces-per-account-2fa-and-app-passwords) (19 August 2026, pre-release, superseded): the server now enforces per-account 2FA and app passwords - [hMailServer 6.2.22-pre2](https://www.hmailserver.co.uk/topic/28174/hmailserver-6.2.22-pre2-dmarc-aggregate-reports-rua-are-now-sent-not-just-consumed) (18 August 2026, pre-release, superseded): DMARC aggregate reports (rua) are now sent, not just consumed - [hMailServer 6.2.22-pre1](https://www.hmailserver.co.uk/topic/28168/hmailserver-6.2.22-pre1-the-built-in-acme-client-never-worked-with-let-s-encrypt) (16 August 2026, pre-release, superseded): the built-in ACME client never worked with Let's Encrypt - [hMailServer 6.0.0-B4](https://www.hmailserver.co.uk/topic/28212/hmailserver-6.0.0-b4-fixes-the-startup-crash-from-the-bundled-vc-runtime) (12 June 2026, pre-release, superseded): fixes the startup crash from the bundled VC++ runtime - [hMailServer 6.0.0-B1](https://www.hmailserver.co.uk/topic/28211/hmailserver-6.0.0-b1-first-regression-validated-build-of-the-modernised-6.0-line) (12 June 2026, pre-release, superseded): first regression-validated build of the modernised 6.0 line - [Full text of the key pages](https://www.hmailserver.co.uk/llms-full.txt) - [Recent topics, RSS](https://www.hmailserver.co.uk/recent.rss) - [Sitemap](https://www.hmailserver.co.uk/sitemap.xml)