Mattermost End of Life (EOL) Dates & Support Timeline

Mattermost release and support pattern

Across the 57 release lines with a published release date, Mattermost has shipped a new line roughly every 4 weeks (median interval). A line typically stays supported for about 3 months from its release to its end-of-life date. 7 of the 57 tracked lines are designated long-term support, which is where the longer windows sit.

Of the 57 release lines tracked, 53 are past end of life and 4 are still within support. The newest line, 11.11, was released September 16, 2026. The next scheduled end of life is 11.9 on October 15, 2026 — 22 days from this build. The longest-supported line currently published is 11.7, to May 15, 2027.

Computed from the tracked release data at every build — the figures above are the dates in the table, restated, not an editorial estimate.

What does Mattermost end of life mean for your organization?

When a version of Mattermost reaches end of life, the maintainers stop issuing security patches. Vulnerabilities discovered after this date are publicly disclosed on the National Vulnerability Database, exploit code appears on GitHub, and your systems remain permanently exposed.

The CVE blind spot: A CVE-based scan does not show the accumulation of unpatched vulnerabilities in EOL software. Some scanners flag unsupported versions of common products, but coverage varies, and none of them give you the date in advance. With a zero-day, nobody knows about the vulnerability. With EOL software, the vulnerability is public — listed, rated, and often weaponized — but no vendor patch is coming. This is one of the most dangerous gaps in enterprise security posture.

Organizations running EOL Mattermost should treat it as a vulnerability class in their risk register, apply compensating controls (network segmentation, enhanced monitoring, access restriction), and prioritize migration to a supported version.

Your options when Mattermost reaches end of life

There are four realistic paths. Which one is right depends far more on how long the system needs to keep running than on the version you are on today.

How to choose, in one question: how many more years does this system need to run? Under a year, extended support (where it exists) is usually cheaper than an emergency migration. One to three years, migrate — support purchased repeatedly costs more than doing the project once, and the project only gets harder as the version ages. Indefinitely, migrate now and plan the next migration before it surprises you.

Worth saying plainly, because vendors selling extended support rarely will: extended support is often the more expensive choice over a multi-year horizon. It is the right answer when a deadline is genuinely unreachable, not as a default. Compare the annual fee against the one-time cost of migrating before committing to either.

Formalizing decisions like this across your estate? Our free EOL policy template is a ready-to-adopt policy with risk tiers, remediation SLAs, and audit mapping — no signup, free to use and share.

Extended Support Options

If you cannot migrate immediately, extended support vendors provide continued security patches for EOL Mattermost versions. This is a bridge, not a permanent solution — plan your migration in parallel.

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