It isn’t really Open Source if it can become not Open Source.
If you have some fos licensed software it will be foss forever, that licence is a contract and doesn’t go away. Now the author(s) of that code can license it to other people or release the newer versions with a different non-foss licence.
Don’t tell Oracle
Open source and FOSS are two different things though. I think Mattermost is open source, just not FOSS and the licencing they mentioned might be wrong (GPL is invasive so they couldn’t have a closed source part IIRC), but it’s still open source as the code is freely available.
Open source and source-available are two different things.
Sure, but which OSD criteria is being broken here?
Yup, migrated to Google chat last week at work. Way worse than Mattermost :(
Eh, that post title is quite sensationalistic.
- Nothing regarding the license has changed in the last 2 years.
- It seems like they consider the non-enterprise code to be licensed under the AGPL:
Thank you for the community discussion around this topic. I do recognize that our licensing strategy doesn’t offer the clarity the community would like to see, but at this time we are not entertaining any changes as such.
UPDATE Feb 2, 2026: To be specific, our license is using standard open source licenses, a reciprocal AGPL license and a permissive Apache v2 license for other areas. Both are widely used open source licenses and have multiple interpretations of how they apply, as showcased in this thread.
When we say we don’t “offer the clarity the community would like to see”, that refers specifically to the many statements in this thread where different contributors are confused by other people’s comments and statements.
For LICENCE.txt itself, anyone can read the history file and see we haven’t materially changed it since the start of the project.
If you’re modifying the core source code under the reciprocal license you share those changes back to the open source community. If you’d like to modify the open source code base without sharing back to the community, you can request a commercial license for the code under commercial terms.
Maybe we can hold the pitchforks a while longer, unless they actually make a negative change.
The contention is that Mattermost say it’s licensed under AGPL but then they add conditions which are incompatible with that license. So it seems they want to give appearance of AGPL but not give the actual rights that come with it. So therefore it’s not AGPL.
I think the problem is that the license grant (that has been in place for a decade) is not that clear.
You are licensed to use compiled versions of the Mattermost platform produced by Mattermost, Inc. under an MIT LICENSE
- See MIT-COMPILED-LICENSE.md included in compiled versions for details
You may be licensed to use source code to create compiled versions not produced by Mattermost, Inc. in one of two ways:
- Under the Free Software Foundation’s GNU AGPL v3.0, subject to the exceptions outlined in this policy; or […]
I read it as releasing the binaries under MIT and granting people an AGPL license for the (non-enterprise) code. Some read it as not granting you the full AGPL rights.
To me, the fact that they advertise Mattermost as “open-source” and the statement on the “reciprocal license” above indicates that Mattermost also reads this as an AGPL license grant. However, they don’t seem to be interested in fully clarifying the license situation. But, I think they would have a very hard time to argue in court that this license doesn’t allow AGPL forks. And I haven’t seen any evidence of them acting against any of the existing forks.
AGPL is restrictive so actually having MIT is a backup option weakens the AGPL license. And in particular having the ability to ship closed source binaries if you wish to, under a commercial license, means AGPL means jack shit here to those who want everything to be copyleft
which conditions on top of AGPL are they adding?
My understanding was (perhaps wrong?) that the “Mattermost Team Edition” is offered under the AGPL, and then the “Enterprise” Editions (starting with the “Entry Edition”) have additional restrictions (including the 10k message limit in the “Entry Edition” that everyone’s been talking about). They do a good job of hiding the “Team Edition” (it’s almost like the don’t really want to have to offer an open-source editions… 🤔), but it is there if you can find it. https://docs.mattermost.com/product-overview/editions-and-offerings.html#mattermost-team-edition
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This seems like your standard open core/dual licensing, CLA controlled BS where open source is indeed treated like an inconvenience… Perhaps with more obfuscation than on average. Probably not really adding requirements on top of AGPL as such but they seem to be offering multiple releases under a more restrictive license either because they have the rights so they can do dual licensing or they keep certain components proprietary and don’t offer those with the team/community editions.
So yeah, probably within their legal rights and I assume there is still a codebase/release that you can use under the terms of the AGPL but they do seem to be looking for ways to make it be used as little as possible.
I could be wrong if the AGPL and other open source parts aren’t enough for actually compiling a functional version of this but this is what it mostly looks like to me.
I Will never understand why the open source community hates the GPL license. Maybe they just haven’t seen themselves how big corporations taking advantage of free individual independent developers. I still remember the core.js developer, whose code is in pretty much every giant framework out there basically begging for any sort of income for his work while his family was going hungry in Eastern Europe. Angular, react, all major frameworks absolutely depend on it and never gave them anything.
(Breathes in…)
Having spent a large part of today wrestling with a selfhosted mattermost upgrade, it would be nice if they spent a bit of time focusing on making this better, like many other things do. Nothing else, at least since we dropped Atlassian selfhosted apps, has been as consistently poor at this.
Changes to supported databases (not once, but twice), forced migrations, breaking change after breaking change (especially of things that could easily be handled automatically but instead block until you’ve found the log error and researched it), and so on. Support, even for commercial customers, is very poor and sometimes extremely rude (at least one senior dev is very opinionated). And things like arbitratrily restricting how many historical messages you can read without a commercial licence shows a deep disrespect for users, plus random feature creep like adding telephony, who actually uses that?
Compare to Teamcity where you click one link in the ui and are pretty confident stuff will work afterwards, and most other selfhosted apps where major distro specific packages are provided, and add a very rapid release cycle, it’s a lot of work to maintain.
Overall, I’m not convinced that Mattermost is a well run project, foss or not. Major changes in direction smack of poor roadmapping and leadership. It would not surprise me at all if the licence issues in the post turned out to be accidental rather than deliberate.
Seriously, if you’re in the market for a chat app - whether it’s free or a thousands-seat enterprise, pick something else. Almost anything else.
I’ve been running self-hosted Mattermost for a medium-sized academic org for a while now, and upgrades have always been a breeze, tbh (but I only use the version with open-source code only – the “Team Edition” --, not the Entry or any of the other Enterprise Editions, so that may be relevant).
Wow, that’s sad
Hence why we need to distinguish between Free-software/Libre & *OpenSource" (& Spurce-Available as well)
honestly with their whole military! fuck yeah!1!! spiel, they can get fucked. along with all other corpos with their gaping assholes to cram evermore cash into them, and that includes element the corp; they got the other fetish - cops.
I just was considering trying it out! Oh well.
From a read of that issue, it looks like it never was.
MostlyMatter (FOSS Mattermost fork without user limits). https://framagit.org/framasoft/framateam/mostlymatter?ref=selfh.st
I learned about this today from the self-host newsletter.
Newsletter, you say?
