grommunio 2026.06.1 is here — our biggest release yet

The countdown is done, and grommunio 2026.06.1 is out. We’ve been calling it our biggest release for a while now, and with it finally shipped, we’re happy to stand by that.

It took a bit over a year, and the work reaches into just about every corner of the stack, from the C++ mail engine up to the ISO you boot. The short version: it runs lighter, it talks to more clients, and it leaves you with even fewer reasons to keep paying Microsoft. The longer version is below.

If there’s one idea holding it all together, it’s that you stay in charge of your own infrastructure. Mail, calendars, files, meetings, identities, and as of this release your AI too, all running on hardware you control, with nothing forced through someone else’s cloud.

grommunio AI, on your terms

The big new arrival in 2026.06.1 is grommunio AI, an assistant that lives inside grommunio Web. It can summarise a single mail or a whole thread, translate messages, and help you write: draft a reply, tighten it up, make it shorter or longer, change the tone, fix the grammar. It also comes with a set of Smart Actions. From a mail it can offer to set up a meeting and invite the people named in it, create a task, save the sender as a contact, or start a reply. Each one opens a dialog that’s already filled in, and nothing happens until you click. You stay in the loop by design.

What matters most to us, though, isn’t the feature list. It’s that you decide which model runs the thing, and where.

Most cloud suites give you exactly one option: the vendor’s AI, in the vendor’s cloud. grommunio AI doesn’t work like that. It speaks two API standards, the OpenAI-compatible one and Anthropic’s, and between them that covers more or less everything worth using:

• free cloud tiers like Google Gemini (the shipped default), Groq and OpenRouter
• the commercial APIs: OpenAI, Anthropic/Claude, Mistral, Azure OpenAI and the rest
• and local models you host yourself, via Ollama, LM Studio, vLLM, llama.cpp or LocalAI

Switch to the local Ollama setup and nothing leaves the building. No key, no outbound call, no third party reading your mail. That’s something Microsoft 365 Copilot can’t offer you at any price.

The privacy side was built to match. The plugin ships switched off. Until an admin turns it on, there are no buttons, no menus, and not a single call to any model. Once it’s on, every user still has to opt in for themselves. The calls happen on the server, never in the browser, and the API key stays in the server config where the browser never sees it. We’ll be straight about the one caveat: point it at a cloud provider and the text you’re working on does go to that provider. Which is exactly why the local, nothing-leaves option is a one-line change away.

gromox: a lighter, faster engine

Underneath everything sits gromox, the engine that lets grommunio speak Exchange. It got a lot of attention this time.

Start with memory. The information store can now split itself up, running a small worker process per mailbox under a lightweight director instead of one big process that only ever grows. Add a heap reaper that hands unused memory back to the system on a schedule, tighter limits on the IMAP daemon, a shorter idle-cache timeout, and a stack of plugged leaks, and the result is easy to state: the server holds onto less memory, so you can fit more mailboxes on the same box.

gromox is also now one of the few open-source groupware servers that speaks IMAP4rev2 (RFC 9051), fresh in this release. It advertises the capability behind the ENABLE handshake and implements the modern command set: ESEARCH, LIST-EXTENDED, server-side MOVE, saved search results, UTF-8 mailbox names, the cleaner status and response codes. Thunderbird and mobile clients get a tidier, more efficient IMAP to talk to, and a good twenty years of accumulated cruft goes away.

Exchange Web Services, the protocol Outlook for Mac and eM Client lean on, grew a great deal. It now handles tasks, calendar occurrences with proper timezones, real delegate management with permission levels, and the full meeting workflow: invitations, cancellations, responses, and a server-side processor that keeps the organiser’s calendar in step. Streaming notifications and room and people lookups landed too. If you’re moving a mixed fleet of clients off Exchange, this is the layer that makes the job boring instead of painful, which is what you want from it.

There’s a brand-new Offline Address Book as well. Outlook’s cached address book has been a sore point for years. gromox now builds and serves one itself, including a from-scratch implementation of Microsoft’s OAB format and its LZX compression, with no Microsoft code anywhere in it.

Mail bodies render better, too. Conversions between HTML, RTF and plain text can hand off to Pandoc and Chawan for higher fidelity, and the in-house RTF reader got a thorough going-over for CJK text, right-to-left scripts, nested tables and the usual Word weirdness.

And then the long tail of fixes nobody writes home about but everybody feels. Outlook no longer loses appointments when you open a shared calendar. Outlook 2010 can log in again under OpenSSL 3. AutoDiscover stopped advertising an OWA endpoint it never had, which had quietly been breaking Thunderbird setup. Recurring meetings keep their timezones straight. The import and export tools also got clearer names, gromox-import and gromox-export.

grommunio Web

Besides being the new home of grommunio AI, the web client kept getting polished where it counts: composing, S/MIME, search, theming. Nothing flashy, just the steady work that keeps it the most capable open-source Exchange web client around.

Shared mailboxes on your phone, at last

Here’s one we’re genuinely pleased about. grommunio-sync now does impersonation over Exchange ActiveSync, so you can put a shared or functional mailbox on a phone with full rights to it, signing in with your own account. Exchange and Microsoft 365 don’t do this over ActiveSync; there you’re stuck adding the mailbox as a separate account or living in webmail.

It works end to end. gromox’s AutoDiscover understands the combined sharedmailbox!user login and enforces it on the server side, checking both who you are and whether you actually hold owner rights on the target, so the phone gets set up straight against the shared store. There’s a safety net as well: a remote wipe on an impersonated session is dialled back to account-only, so nobody wipes a personal device by accident.

A rebuilt admin, and DKIM out of the box

The admin web interface has been rebuilt in TypeScript. The whole codebase moved over, file by file, to a strictly-typed setup with strict mode on and no JavaScript left behind. The payoff is fewer things breaking at runtime and a console that’s a lot easier to work on and contribute to.

On the API side, DKIM is now handled for you. You can generate a signing key per domain right from the admin UI, and grommunio hands back the public record to paste into DNS, so there’s no more fishing around on the command line with rspamadm and openssl. This release also sorted out default and anonymous permissions on public folders and tightened a few directory-integration paths along the way. Once your records are published, grommunio’s existing DNS health check will tell you whether SPF, DKIM, DMARC, MX and the rest line up.

The rest of the suite

grommunio Meet got a big refresh, including the thing self-hosters keep asking for: a central, managed STUN/TURN relay (turn.grommun.io). TURN is what gets video calls through corporate firewalls and NAT, and running a good relay yourself is honestly fiddly. So if a local TURN setup isn’t realistic for you, Meet comes already wired up to a hosted one, with a fallback over port 443 that looks like ordinary HTTPS and nearly always gets through. You can still point it at your own coturn whenever you want. The whole Jitsi stack moved to a current build on JDK 17, and lobby and breakout rooms are switched on out of the box.

grommunio Files moved up a full generation. The interface is fresher, it’s faster and more secure than the version before it, and collaborative in-browser editing of office documents is built in. It carries grommunio’s branding, signs people in with their existing grommunio accounts, and upgrades older installs on its own, in place. It’s the self-hosted answer to OneDrive and SharePoint.

grommunio Keycloak moved to Keycloak 26.6.4, the identity provider behind single sign-on across Web, Admin, Files and Meet from one grommunio login. Think of it as your own Entra ID that never phones home. Its configuration also moved under /etc, so your settings now survive upgrades.

grommunio Archive was overhauled to its new 1.4 generation. It’s our email archiving and compliance solution, and it runs as a regular service alongside the rest of grommunio: a web interface for searching and reviewing mail, full-text search underneath, and an SMTP listener that takes a copy of messages as they pass through. It was rebuilt for the Leap 16.0 and PHP 8 base, and the new engine adds direct IMAP import for pulling existing mailboxes in, on top of the things it’s really there for: archiving and retention rules, legal hold, deduplication, digital fingerprinting and verification, tagging, export and restore, audit logs, and bulk import from sources like Google Workspace and Microsoft 365.

grommunio Desk, the desktop client, is here as 1.2:

• Spell checking in text fields, based on your system languages
• Zoom in and out of the server view, with a reset to the default level
• A right-click context menu with spelling suggestions, copy, paste and more
• Each server now runs in its own isolated session, so logins and cookies stay separate between servers
• You can edit the name of a configured server, plus a new menu option to reload the current one
• Clearer server icons in the title-bar menu
• Existing settings migrate automatically to the new format, on top of an updated Electron base
• Fixes for server-URL validation, missing macOS keyboard shortcuts, the server-view loading state, and the buttons in dialog windows

For the standards crowd, grommunio DAV can now publish the company Global Address List as a read-only CardDAV address book, and it remembers per-folder CalDAV and CardDAV settings, so the calendar colours and ordering you set in Apple Calendar finally stick. grommunio Index 1.6 made server-side full-text search more configurable and steadier under load.

A fresh platform: openSUSE Leap 16.0

The whole appliance was rebuilt on openSUSE Leap 16.0, swapping the ageing 15.x base for a current, maintained one with a newer kernel, toolchain and crypto stack. And it’s not only the VM image. Every guided install target moved to 16.0: the VMware/OVA appliance, the install ISO, the offline all-in-one ISO for air-gapped sites, and the container/compose stack, now on Leap 16.0 with MariaDB 11 and de-privileged. Networking switched over to systemd-networkd, and grommunio-setup is now safe to re-run, so you can add or remove roles on a live system without a clean reinstall, on both 15.6 and 16.0.

Debian, properly this time

grommunio grew up on openSUSE and RPM, and for a long time that was that. Not anymore. With 2026.06.1 there are native .deb packages for the whole stack, the gromox engine and every front-end included, built the proper Debian way. The setup tooling learned to work out what it’s running on and do the right thing: write apt sources, import signing keys into the keyring, and drive apt on Debian 13 and Ubuntu 24.04 and 26.04 LTS, right next to openSUSE and RHEL.

The packages are all there. We’re bringing them to general availability on purpose, one component at a time and with selected partners first, so we can be confident each one behaves before it goes out to everyone. The aim is plain: on Debian, the same grommunio you already run on openSUSE.

Documentation, rebuilt

Last on the list, docs.grommunio.com has been rebuilt from the ground up on a modern static-site stack, with fast search across every page and a clean split into User, Administration and Development sections. There’s a fair bit of new material in there too, including a high-availability clustering guide, a Kerberos single sign-on walkthrough for transparent domain-joined Outlook logins, a fuller Exchange-to-grommunio migration guide, and a rewritten container chapter for Leap 16.0. It’s still going up as we speak, so a few corners are being finished off, but most of it is already live at docs.grommunio.com.

Go get it

2026.06.1 is a release we’re proud of. It’s leaner where it counts, broader where it matters, and it doesn’t give an inch on the thing grommunio has always been about: your data staying yours. Mail, calendars, files, meetings, identities, and now AI, all on infrastructure you run.

Existing installs can update through the usual grommunio update process. A big thank-you to the customers and partners whose feedback shaped this one, and to everyone who builds grommunio out in the open.

Join the conversation over in the grommunio community.