Yes and no, and the distinction is the entire question. Zimbra is still open source software under licences that permit commercial use without a fee. Zimbra also stopped publishing installable Open Source Edition builds after 8.8.15, so "is Zimbra free" now depends on whether you are willing to compile it yourself.
That gap catches out a lot of people in Kenya who ran the free edition happily for years, went looking for the current one, and found a licence prompt where the download used to be. We run Zimbra mail servers for organisations across East Africa on both editions, so here is the actual state of it.
The licence and the binary are two different things
The source code remains published and actively maintained. The server components are GPL v2 and the web client is under the Common Public Attribution License, both of which permit you to run Zimbra commercially without paying anyone. Nothing about that has changed and nothing suggests it is about to.
What changed is distribution. Zimbra stopped producing the ready-to-install Open Source Edition packages at the end of 2023. From version 9 onward there is no official free installer to download, and Zimbra 10 will not complete an installation without a licence key, trial keys included.
So the software is free in the sense that matters legally, and not free in the sense that matters on a Tuesday afternoon when you want a mail server running.
What running the open source route actually involves
You build it from source. The build tooling is public, the process is documented, and it works. Several third parties also publish compiled open source builds, which is what most people who go this route actually use.
Neither of those is free the way the old download was free. Building from source means you own the build pipeline: you rebuild for every security patch, and given that CISA currently lists 18 Zimbra vulnerabilities as confirmed exploited in the wild, patching promptly is not optional. Using someone else's build means trusting a third party with the binaries that handle all your organisation's mail, which is a real decision rather than a formality, and one worth thinking about harder than most people do.
Either way you also lose the Network Edition features, and the one that hurts is the backup and restore tooling. On the open source route you are assembling your own backup strategy, which is doable and is exactly the thing people put off until the morning they need it.
When we recommend which
For a small technical team that genuinely runs Linux, wants full control and has someone who will own the build and patch cycle, the open source route is legitimate and we support clients on it. Our Linux infrastructure work is largely this kind of thing.
For everyone else, and that is most organisations, the licence buys you supported binaries, the backup tooling and somebody to escalate to. Weighed against the cost of the person who would otherwise maintain your build pipeline, it is usually the cheaper of the two. The full arithmetic, including where the hosted suites beat both, is in what a Zimbra server costs against Microsoft 365.
The version you should not be running is the one this question usually arrives attached to: an 8.8.15 install still going because it was the last free download. That release lost technical guidance at the end of 2024, and free stopped being the relevant adjective some time ago.
If you are on the free edition and trying to work out what your options are without buying something you do not need, send us the version and mailbox count through the scoping form or on WhatsApp at +254 713 403 044. We will tell you if the honest answer is to stay where you are.