Open365

Open365 was a free, open-source, self-hosted alternative to Microsoft Office 365, aimed at small organisations and admins who wanted online documents, file sync and mail on their own Linux server. Before you look for an Open365 download, know the key fact: the project is discontinued. Its main repository has had no changes since December 2016, the open365.io service is gone, and there is no official successor.

Open365 was built by the eyeOS team, backed by Telefónica, and released as a public beta in 2016 under the AGPL-3.0 licence. It combined LibreOffice Online for documents, Seafile for file sync and sharing, KDE Kontact for mail, contacts and calendar, and Jitsi for messaging, all inside the eyeOS web desktop. This page explains what it was, what to do with an old install, and what to use today. It has no connection to Microsoft Office 365.

Open365 at a glance

What it does

These are the capabilities the 2016 beta offered. None of them receive updates or security fixes today.

• Browser-based editing of text documents, spreadsheets and presentations through LibreOffice Online.
• File storage, sync and sharing based on Seafile.
• Mail, contacts and calendar through KDE Kontact, delivered in the browser.
• Instant messaging and calls via Jitsi.
• A single web desktop (eyeOS) tying the applications together, with user and domain management from the command line.
• Docker-based installation from one installer script.

How sysadmins use it

Find and retire a leftover Open365 server

1. Look for the old stack on Linux hosts: docker ps -a and docker images will show many eyeOS and Open365 containers if it is still running.
2. Treat any internet-facing instance as a security risk: its LibreOffice Online, Seafile and web components have not been patched since 2016.
3. Restrict it to the internal network or shut it down while you migrate data.

Get data out

1. Inventory which users stored files and which used mail.
2. Copy documents out through the web interface while the stack still runs, then verify file counts.
3. If users kept mail in it, export mailboxes with whatever access the old server provides (for example an IMAP client) and import them into the new mail system.
4. When everything is verified, remove the stack with the installer’s own command: sudo ./open365 destroy. This deletes everything related to Open365, so run it only after you have a backup.

Build a maintained replacement

The closest modern equivalent is Nextcloud with Nextcloud Office (Collabora Online) or ONLYOFFICE. Nextcloud All-in-One installs the whole stack with one container on a Docker host:

sudo docker run 
  --init 
  --sig-proxy=false 
  --name nextcloud-aio-mastercontainer 
  --restart always 
  --publish 80:80 
  --publish 8080:8080 
  --publish 8443:8443 
  --volume nextcloud_aio_mastercontainer:/mnt/docker-aio-config 
  --volume /var/run/docker.sock:/var/run/docker.sock:ro 
  ghcr.io/nextcloud-releases/all-in-one:latest

Then open the AIO interface on port 8080, enter your domain and enable Nextcloud Office. For mail, pair it with a maintained mail server rather than rebuilding the old Kontact setup.

Install and first run

For completeness, this is how the beta was installed. It is documented here so admins can recognise an existing deployment, not as a recommendation.

• Server: Linux with Docker, docker-compose 1.3 or higher and Python 3. The README listed Python modules (mysqlclient, pymongo, ldap3, requests) for Debian/Ubuntu and Fedora.
• SELinux had to be disabled, which is one more reason not to run it on a modern hardened host.
• Disk: the installer pulled Docker images totalling more than 15 GB in the beta.
• Commands: sudo ./open365 install to deploy, sudo ./open365 user-create to add users, sudo ./open365 create-domain for extra domains.
• Clients: web browser; there was nothing to install on Windows or macOS for normal use.

Today the images reference software from 2016, and you should expect the install to fail or produce an unpatched system.

Limitations

• Discontinued since 2016: no releases, no security updates, no support.
• It never left beta and never published versioned releases.
• No official successor and no migration tool.
• Heavy footprint for its time (15+ GB of images) and required SELinux to be disabled.
• Its components (LibreOffice Online, Seafile, Kontact, Jitsi) have all moved on; their current versions are better used directly.

Open365 vs alternatives

FAQ

Is there still an Open365 download?

Only the old source code and installer scripts on GitHub. There has been no update since December 2016, and the images it pulls are outdated, so it is not suitable for new installs.

Is Open365 related to Microsoft Office 365?

No. Open365 was an independent open-source project that positioned itself as an alternative to Office 365 and Google Drive. Searches for “Open365 Outlook” or “Open365 login” usually mean Microsoft’s product.

Is Open365 free?

Yes, it was free and open source under AGPL-3.0. Being free does not make it safe to run today, because it is unmaintained.

What replaced Open365?

Nothing official. The usual replacement is Nextcloud with Nextcloud Office (Collabora Online) or ONLYOFFICE, plus a separately maintained mail server.

Was Open365 available for Windows or Mac?

The server ran on Linux under Docker. Users worked in a web browser, so the operating system on the desktop did not matter.

What was Open365 built on?

LibreOffice Online for documents, Seafile for files, KDE Kontact for mail and calendar, and Jitsi for messaging, joined in the eyeOS web desktop.

How do I remove an old Open365 installation?

Back up user data first, then run sudo ./open365 destroy from the installer directory, which removes everything the installer created.

Last checked against official sources: 1 October 2026 (developer website: github.com). Versions and licence terms change — confirm on the developer's site before deploying in production.