Mozilla Firefox end of life: end of support by version
Mozilla · Browsers & Clients
For Mozilla Firefox by Mozilla, patchletter knows 4 support cycles. 2 of them have already ended and receive no more security updates. The current version of Mozilla Firefox is 158.0. The cycles come from the open endoflife.date project, last reconciled on 04/09/2026.
When does support end for which Mozilla Firefox 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 |
|---|---|---|---|
| 155 (Rapid Release) | 155.0 | 36 days ago | End of Life |
| 153 ESRLTS | 153.2.0 | no date on record | supported |
| 140 ESRLTS | 140.15.0 | 8 days ago | End of Life |
| 115 ESR (nur Altsysteme)LTS | 115.40.0 | no date on record | supported |
Which Mozilla Firefox 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.
- Mozilla Firefox 155 (Rapid Release)155.0
- Mozilla Firefox 140 ESR140.15.0
Where does the EOL data for Mozilla Firefox come from?
From the open endoflife.date project, which collects vendors' official support commitments. patchletter reconciles the cycles daily; the Mozilla Firefox 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 Mozilla Firefox 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.