Mattermost 9.11 End of Life
Support dates and upgrade guidance — rebuilt from live data.
Mattermost 9.11 reached end of life on 15 May 2025. It no longer receives security fixes.
Support timeline
Official dates from the Mattermost release process.
| Milestone | Date | Status |
|---|---|---|
| Initial release | 2 Aug 2024 | — |
| End of life | 15 May 2025 | 1.2 years ago |
| Latest release | 9.11.18 · 22 Jul 2025 | final |
Where to go from 9.11
Recommended target: Mattermost 11.9 (supported until 15 Oct 2026).
The newest actively supported branch is Mattermost 11.9 (latest release 11.9.0).
Frequently asked questions
Is Mattermost 9.11 still safe to use?
Mattermost 9.11 reached end of life on 15 May 2025, 451 days ago, and is no longer covered by standard support. Running it means no guaranteed security fixes.
Can I still download Mattermost 9.11?
Yes — the final release (9.11.18) generally remains available from vendor archives and OS package mirrors, but installing it means running software with known, unpatched vulnerabilities.
What should I upgrade Mattermost 9.11 to?
Upgrade to Mattermost 11.9, the newest actively supported branch (supported until 15 Oct 2026).