AnnexSERVER · AnnexGroup
The groupware server
you own.
AnnexGroup is a groupware server for self-hosting: mail, calendar, contacts, tasks and notes in a single binary, on your own hardware. With AI assistants whose data never leaves the building — without an external model provider.
Full feature set, no registration, no payment details.
3 reasons that make the difference
One file, not a project
A single server process with built-in SMTP, IMAP and web interface. Not a dozen services somebody has to orchestrate first.
macOS and Linux as equals
The same codebase for Apple Silicon and Linux on x86-64 and ARM — not a second-class port, but an equal target. The Intel package is built, notarized and has run under Rosetta, but it has not been tested on an Intel Mac.
AI agents in your own house
Every user can create sub-accounts for assistants — with autonomy levels, an incubation period and approval before anything is sent. How it works
Why now
For self-hosted servers, several things have started to slide at once. The dates are fixed:
| What | When | What follows |
|---|---|---|
| Exchange Server 2016 and 2019 | 2025-10-14 | Support ended; Microsoft offers paid, time-limited Extended Security Updates. The successor Exchange SE is a subscription; Microsoft raised prices by 10 % for servers and 15–20 % for access licences (source: Practical 365). |
| Kopano Groupware and Core | 2024 | According to Kopano, the older Kopano Groupware reached end of life in 2024; Kopano names “Kopano Cloud” as the successor product. Other sources give 31 March 2025 as the end of support; we could not confirm that on Kopano’s own site. |
| Zimbra 9.0.0 | 2025-06-30 | According to the Zimbra wiki, technical guidance (“End of Technical Guidance”) for Zimbra 9.0.0 ends on 30 June 2025. |
| EWS in Exchange Online | from October 2026, fully April 2027 | Microsoft is switching off Exchange Web Services. The successor, Microsoft Graph, exists exclusively in the cloud — there is no replacement for self-hosting. Integrations that run over EWS today have to be rebuilt. |
On top of that, prices are moving the other way: Microsoft 365 Business Standard rises from $12.50 to $14 per user and month on 2026-07-01, with Copilot at $21–30 extra. Google Workspace raised prices by 16–22 % in 2025.
Sources
What is inside
- SMTP and IMAP with STARTTLS
- A queue with retries
- DKIM signing
- Suggestions for SPF, DMARC and MTA-STS records
- Sieve filters
- Rspamd and ClamAV integration
- Out-of-office replies and signatures
Groupware
- Calendars with invitations
- Contacts with vCard import and export
- Tasks
- Notes
- Shared spaces for teams
- Sharing between users
- Colour-coded categories
- Full-text search across everything
Devices and clients
CalDAV and CardDAV for iPhone, iPad and Mac, a web interface for every browser, installable as a web app, IMAP for Apple Mail, Outlook and Thunderbird. Proven: with Thunderbird, autoconfiguration picks up the server name, folders, address book and two calendars; with Apple Mail, sending, receiving and saving drafts are additionally tested, including delivery to the inbox (not spam). Setup with just the email address does not work with Apple Mail, only operation afterwards. Classic Outlook on Windows is also proven: mail via IMAP, calendars and contacts via the Outlook CalDav Synchronizer add-on — third-party software under AGPL, for which we provide no support; detection runs via /dav/. Appointments and contacts were tested in both directions; invitations and attendees come through. OAuth2 and API keys for your own integrations. Evolution has been measured — the run happened in a Docker container on Apple Silicon, not at a Linux workstation.
Administration
- Setup wizard
- Domain and user management
- Self-check with a traffic-light display
- Protection against unauthorised login attempts
- Blocklists
- Backup and restore
- Certificates via Let’s Encrypt or your own
Terms and standards
The technical terms on this page, briefly explained, each with its IETF (Internet Engineering Task Force) standard.
- IMAP — Internet Message Access Protocol: mail programs read messages and manage folders directly on the server. (RFC 9051)
- SMTP — Simple Mail Transfer Protocol: sending and delivering mail between servers and from mail programs to the server. (RFC 5321)
- CalDAV — Calendaring Extensions to WebDAV: synchronises calendars and events between server and devices. (RFC 4791)
- CardDAV — vCard Extensions to WebDAV: synchronises address books and contacts between server and devices. (RFC 6352)
- DKIM — DomainKeys Identified Mail: the sending server signs messages, the recipient verifies the signature. (RFC 6376)
- SPF — Sender Policy Framework: a DNS record states which servers may send for a domain. (RFC 7208)
- DMARC — Domain-based Message Authentication, Reporting and Conformance: states what happens to messages that fail SPF or DKIM. (RFC 7489)
- MTA-STS — SMTP MTA Strict Transport Security: enforces encrypted connections for mail transport between servers. (RFC 8461)
- Sieve — A language for server-side mail filters, for example sorting into folders or out-of-office replies. (RFC 5228)
Looking after several customers?
AnnexGroup serves multiple tenants on one installation — each customer with its own domain admin role, strictly separated: full-text search, address book, sharing and free/busy stop at the domain boundary. A tenant admin works in the web interface and through the API: users, groups, rooms, aliases, shared mailboxes, their own domain and the retention rules of their domain. Anything affecting the whole installation stays with the operator.
Included in the shipped build
The Exchange habits worth keeping
People leaving Exchange ask about the small things first: can a colleague see when I am free? Will I get the meeting room? Can I write to the whole department? Those paths are built and covered by tests.
Free/busy
When is a colleague available — visible in your own calendar app, without anyone giving away what the appointment is. Only time goes out: no title, no location, no attendees.
Rooms and equipment
A meeting room has its own calendar and answers for itself: accept when free, decline when booked — naming the conflicting appointment as the reason.
Global address list
Colleagues are findable on a freshly set up device, without anyone entering contacts by hand. Limited to your own domain.
Distribution groups
One address for the whole department, nested as deeply as you like. Anyone in two subgroups still receives the mail exactly once.
Send as, send on behalf
An assistant writes from the management mailbox — either visibly on their behalf, or entirely in the name of the mailbox.
Out of office with a period
A start and an end instead of a switch you forget on the day you return. Separate texts for inside and outside, because your stand-in's extension does not belong out there.
Rules on the server
File, forward, reply, discard — even when no mail program is running.
Take public folders along
The folder structure from Exchange is mapped onto shared spaces and mailboxes. The mapping is settled before the move and can be changed.
What this means, and what it does not. These features are in the build you download today and covered by automated tests. What AnnexGroup deliberately cannot do is stated openly in the comparison table.
What you pay
Buy once, use indefinitely — including all updates of major version 1.x. Tiers and terms are on the pricing page.
An office with 25 workplaces pays €495 once under the introductory offer — net of VAT.
Frequently asked questions
What happens when the trial expires?
Mail reception keeps running — no messages are lost. Sending and administration are locked until a licence is installed. Your data is fully preserved.
Can I move the licence to another server?
Yes. The licence covers your installation, not a specific machine. When you change servers, you install the same licence file again.
Do I need an internet connection for the server to run?
Not for operation — the licence is verified locally, there is no phone-home to us; the only regular connection is the update check, which can be switched off. Only on the very first start under macOS does the operating system check once with Apple whether the program is notarized. Never again after that.
Does AnnexGroup support Outlook?
Over IMAP for mail and CalDAV/CardDAV for calendars and contacts — in the browser via the web interface, on a Mac for example with Apple Mail and Apple Calendar. As server protocols, AnnexGroup speaks neither MAPI nor EWS; out of Exchange, however, it reads via EWS completely and fetches calendars, contacts, tasks and notes itself, without a Mac. Classic Outlook on Windows gets mail that way; calendars and contacts run via the Outlook CalDav Synchronizer add-on — third-party software under AGPL, for which we provide no support; detection runs via /dav/ and is proven: appointments and contacts in both directions, invitations and attendees come through. We would rather say so up front.
What happens at version 2.0?
With a purchase at the regular price, all updates up to and including version 1.x are included — permanently. The jump to 2.0 will be priced separately. Purchases at the introductory price — by 30 November 2026 inclusive — additionally include all updates up to and including version 2.0. Your licence does not expire in the process: you can keep working on your version indefinitely.
Can we test first?
14 days with the full feature set, without registration and without payment details. If the trial expires without a decision, mail reception stays active — no messages are lost. Sending and administration are locked until a licence is installed.
Frankly speaking
AnnexGroup is young. It does not replace every feature Exchange has accumulated over twenty years: no MAPI, no EWS and no ActiveSync as a server protocol. How classic Outlook is connected anyway is explained further up under “Does AnnexGroup support Outlook?”. We put this here rather than in the small print, so you know before you download and not after.
Everything it does, you can try in full for 14 days — without registration and without payment details.