Progressive Robot's fork of hMailServer: a free, open-source mail server for Windows and Linux (SMTP, IMAP and POP3, webmail, a REST API). AGPL-3.0-or-later. Maintained by Progressive Robot Ltd, separately from the original hMailServer.

The package hmailserver is built from the latest release's source tarball, https://gitlab.com/hmailserver/hmailserver/-/releases, when the project's CI has verified that release (its obs-publish job). Source and issues: https://gitlab.com/hmailserver/hmailserver