Firefox ESR 140

Firefox ESR 140 reached end of life on October 13, 2026 and no longer gets security updates.

Status: End of life
Released: June 24, 2025
Security updates until: October 13, 2026
Long-term support release: Yes
Official lifecycle page: whattrainisitnow.com
Checked on: October 19, 2026

Firefox ESR 140 has reached end of life and no longer gets security updates. Mozilla released it on June 24, 2025. The last ESR 140 release is 140.17, from September 29, 2026. Installations moved to ESR 153 on October 13, 2026; Mozilla’s ESR channel now ships Firefox 153.5.0.

Product: Firefox ESR
Version: 140
Sources: Page URL
Mozilla release calendar https://whattrainisitnow.com/release/?version=esr

Page	URL
Mozilla release calendar	https://whattrainisitnow.com/release/?version=esr

Questions

When did Firefox ESR 140 reach end of life?

Security updates for Firefox ESR 140 ended on October 13, 2026, when installations moved to ESR 153.

Is Firefox ESR 140 still supported?

No. As of October 19, 2026, Firefox ESR 140 no longer gets security updates.

When was Firefox ESR 140 released?

Firefox ESR 140 was released on June 24, 2025.

Where do the Firefox ESR 140 dates come from?

From the vendor’s official pages (Mozilla release calendar), checked on October 19, 2026.

Sources

Every date comes from the vendor’s official lifecycle or release page: Microsoft Lifecycle and Windows release health, Ubuntu’s release cycle, Debian releases, the Python developer guide, the Node.js release schedule, php.net, Oracle’s Java SE support roadmap and Lifetime Support Policy, the .NET support policy, PostgreSQL versioning, Mozilla’s release calendar and Google’s Pixel update policy. Each record links its sources and shows the date they were checked.