Zimbra Open Source Edition
Downloads
-
- Zimbra OSE Source
- Zimbra OSE Source Build Manifest (ZIP)
- Version
- 10.1.16
- Size
- 0.26 MB
- File
- Source
Description
Zimbra Open Source Edition (OSE) is the source-available community edition of Zimbra Collaboration, a self-hosted email and groupware platform for organizations that want to operate messaging infrastructure on their own systems.
The suite combines mailbox services, a browser-based client, calendars, contacts, tasks, administration tools, and extensibility through Zimlets. It is intended for server deployment rather than installation as a desktop email client, so evaluation should include DNS, TLS certificates, mail routing, storage, backups, monitoring, spam filtering, and ongoing security maintenance.
The current verified FOSS source release is version 10.1.16, published on March 9, 2026. Zimbra publishes the source and build orchestration through its official GitHub organization, but does not publish a ready-to-install OSE binary for this release. The package listed here is the tagged zm-build source manifest used to retrieve and assemble the component repositories.
The displayed 1.5 million download total is a conservative FossHub estimate of worldwide historical OSE server and source downloads, not a FossHub click count or an audited current vendor total. It is anchored to Zimbra's 2014 report of more than one million open-source server downloads, with a modest allowance for subsequent official binary releases and later source distribution.
Zimbra Open Source Edition Features
Zimbra OSE brings core communication data into one server-managed environment. Administrators can provision domains and accounts, apply service settings, manage quotas, and expose mailboxes to the web interface or standards-based clients.
Exact capabilities depend on the source components included in a build. Features advertised for Zimbra Network Edition, including licensed modules and some newer interface or mobility functions, should not be assumed to be present in an OSE build.
- Self-hosted email delivery, mailbox storage, search, folders, tags, filters, and distribution lists.
- Shared calendars, contacts, tasks, scheduling, and resource booking.
- Browser-based user access plus IMAP and POP support for compatible mail clients.
- CalDAV and CardDAV interoperability for compatible calendar and contact clients.
- Administration console and command-line tools for accounts, domains, classes of service, quotas, and server configuration.
- Zimlet extension framework for integrating additional actions and services.
- Single-server and multi-server architecture options for different deployment sizes.
Zimbra Open Source Edition Review
Zimbra OSE remains relevant when data location, source visibility, integration flexibility, and control over the mail platform matter more than turnkey installation. Its long-established mailbox and collaboration model can support organizations with the Linux, networking, security, and mail-deliverability expertise needed to run it properly.
That control carries a substantial operational cost. This is not a prebuilt appliance, and version 10.1.16 is distributed as source code rather than an official OSE installer. Teams should budget time for reproducible builds, dependency validation, upgrades, vulnerability response, backup testing, and recovery procedures.
Source Package and Community Builds
The listed ZIP archive represents the official tagged build repository, not a complete installer and not every component source repository in one file. The build manifest identifies the component tags required to assemble a FOSS build. Use the official FOSS source release index to confirm release status before building.
Zimbra's wiki also maintains a community builder list for users seeking binaries. Those packages are produced by third parties, so their build scripts, provenance, update cadence, checksums, and support terms need independent review. FossHub does not present those community binaries as official Zimbra packages.
Administration and Compatibility
A production deployment needs a supported Linux environment, correct hostname and DNS records, working forward and reverse resolution, TLS, adequate storage, and a documented mail migration plan. Administrators should test the build in an isolated environment before introducing real accounts or routing production mail.
Client compatibility is broad at the protocol level, but feature parity varies. IMAP and POP cover mail access, while calendar and contact synchronization depend on client support and configuration. Licensed Network Edition integrations must be evaluated separately from the open-source components.
Who Should Use Zimbra OSE?
Zimbra OSE suits experienced administrators, service providers, educational institutions, and organizations that need an auditable, customizable collaboration stack and are prepared to own its lifecycle. It can also be useful for developers studying or extending Zimbra's server components.
It is a poor fit for teams expecting a one-click mail server, vendor-built OSE installers, or bundled commercial support. Before adopting it, compare the operational effort with a supported Zimbra edition or another maintained mail platform, and verify that the FOSS feature set covers every required workflow.
