Firefox ESR end of life: end of support by version
Mozilla · Browsers & Clients
For Firefox ESR by Mozilla, patchletter knows 4 support cycles. 2 of them have already ended and receive no more security updates. The current version of Firefox ESR is 153.5.0esr. The cycles come from the open endoflife.date project, last reconciled on 04/09/2026.
When does support end for which Firefox ESR version?
A cycle is a maintained version line. Where a date is given, support ends on that day — after it the vendor ships no more security updates for that line.
| Cycle | Latest version | End of support | Status |
|---|---|---|---|
| 153 (aktueller ESR)LTS | 153.2.0 | no date on record | supported |
| 140LTS | 140.15.0 | 8 days ago | End of Life |
| 128LTS | – | 400 days ago | End of Life |
| 115 (nur Windows 7/8/8.1 und macOS 10.12-10.14)LTS | 115.40.0 | no date on record | supported |
Which Firefox ESR versions no longer receive security updates?
2 of 4 cycles have ended. If you run one of those lines, the vendor ships you no more patches — not even for critical flaws.
- Firefox ESR 140140.15.0
- Firefox ESR 128
Where does the EOL data for Firefox ESR come from?
From the open endoflife.date project, which collects vendors' official support commitments. patchletter reconciles the cycles daily; the Firefox ESR data is as of 04/09/2026. In case of doubt the vendor's own lifecycle page applies — patchletter deliberately stores no vendor full texts.
New Firefox ESR versions by email
Tick the product and patchletter reports new releases by email. The update email costs nothing, and one click stops it again. The warning 90, 30 and 7 days before support ends is part of patchletter Pro.