Using a supported browser version is crucial for web security. If you’re using Mozilla Firefox, understanding when your current version will reach end-of-life and when to update is essential for maintaining a secure browsing environment. This guide covers Firefox’s various release channels and their end-of-life schedules, along with practical information for IT professionals and system administrators.
1. Mozilla Firefox Release Channels and Characteristics
Firefox offers multiple release channels to meet different user requirements. Here’s an overview of each channel’s characteristics.
Standard Firefox Release (Stable)
The most commonly used stable version, with new major versions released every 4 weeks. Support for the previous version ends immediately when a new version is released, making automatic updates essential.
Firefox ESR (Extended Support Release)
Designed for organizations like enterprises and educational institutions that deploy Firefox at scale. Supported for approximately 54 weeks (1 year), focusing on security and stability fixes rather than new features.
Developer Channels
- Firefox Beta: Preview of the next stable release (4-week cycle)
- Firefox Developer Edition: Beta-based version with enhanced developer tools
- Firefox Nightly: Daily builds with the latest development features
2. Currently Supported Firefox Versions (September 2025)
Based on Mozilla’s official support information, here are the currently supported Firefox versions:
| Version | Release Type | Release Date | End of Support | Notes |
|---|---|---|---|---|
| 143.x | Standard Release | September 16, 2025 | October 14, 2025 | Current Latest |
| 142.x | Standard Release | August 19, 2025 | September 16, 2025 | End of Life |
| 141.x | Standard Release | July 22, 2025 | August 19, 2025 | End of Life |
| 128.x | ESR | July 9, 2024 | September 16, 2026 | Current ESR |
| 115.x | ESR (Legacy) | July 4, 2023 | March 2026 | Legacy OS Only |
3. Firefox ESR Extended Support Policy
Mozilla announced on September 4, 2025, that Firefox ESR 115 support will be extended until March 2026 for users on Windows 7, 8, 8.1, and macOS 10.12-10.14.
Extended Support Target Operating Systems
- Windows: Windows 7, Windows 8, Windows 8.1
- macOS: 10.12 Sierra, 10.13 High Sierra, 10.14 Mojave
This extended support addresses users who cannot upgrade their hardware. Mozilla’s telemetry data shows that 6.7% of Firefox users still run Windows 7, influencing this decision.
4. Complete Firefox Version Support Schedule
Early Firefox Versions (0.1~4.0)
| Version | Release Date | End of Support | Support Period | Key Features |
|---|---|---|---|---|
| 0.1 | September 23, 2002 | December 7, 2002 | Preview | Phoenix branding |
| 1.0 | November 9, 2004 | November 30, 2005 | 1 year 1 month | First stable release |
| 1.5 | November 30, 2005 | October 24, 2006 | 11 months | Automatic updates |
| 2.0 | October 24, 2006 | June 17, 2008 | 1 year 8 months | Improved tabbed browsing |
| 3.0 | June 17, 2008 | June 30, 2009 | 1 year 1 month | Smart location bar |
| 3.5 | June 30, 2009 | January 21, 2010 | 7 months | TraceMonkey engine |
| 3.6 | January 21, 2010 | March 22, 2011 | 1 year 2 months | Personas themes |
| 4.0 | March 22, 2011 | June 21, 2011 | 3 months | Last before rapid release |
Rapid Release Era (5.0~Present)
2011-2015: 6-Week Release Cycle
| Version | Release Date | End of Support | Cycle | ESR Status |
|---|---|---|---|---|
| 5.0 | June 21, 2011 | August 16, 2011 | 8 weeks | Rapid release begins |
| 6.0 | August 16, 2011 | September 27, 2011 | 6 weeks | |
| 7.0 | September 27, 2011 | November 8, 2011 | 6 weeks | |
| 8.0 | November 8, 2011 | December 20, 2011 | 6 weeks | |
| 9.0 | December 20, 2011 | January 31, 2012 | 6 weeks | |
| 10.0 | January 31, 2012 | March 13, 2012 | 6 weeks | First ESR |
| 11.0~16.0 | March~October 2012 | 6 weeks after each | 6 weeks | |
| 17.0 | November 20, 2012 | January 8, 2013 | 7 weeks | ESR Branch |
| 18.0~23.0 | January~August 2013 | 6 weeks after each | 6 weeks | |
| 24.0 | September 17, 2013 | October 29, 2013 | 6 weeks | ESR Branch |
| 25.0~30.0 | October 2013~June 2014 | 6 weeks after each | 6 weeks | |
| 31.0 | July 22, 2014 | September 2, 2014 | 6 weeks | ESR Branch |
2015-2019: 6-8 Week Release Cycle
| Version | Release Date | End of Support | Key Features | ESR Status |
|---|---|---|---|---|
| 32.0~37.0 | September 2014~March 2015 | 6 weeks after each | Stabilization | |
| 38.0 | May 12, 2015 | July 2, 2015 | ESR Branch | ✅ |
| 39.0~44.0 | July 2015~January 2016 | 6 weeks after each | 64-bit Windows | |
| 45.0 | March 8, 2016 | April 26, 2016 | ESR Branch | ✅ |
| 46.0~51.0 | April 2016~January 2017 | 6-8 weeks after each | Rust integration | |
| 52.0 | March 7, 2017 | April 19, 2017 | ESR Branch | ✅ |
| 53.0~59.0 | April 2017~March 2018 | 6-8 weeks after each | Quantum begins | |
| 60.0 | May 9, 2018 | June 26, 2018 | ESR Branch | ✅ |
| 61.0~67.0 | June 2018~May 2019 | 6-8 weeks after each | WebRender | |
| 68.0 | July 9, 2019 | September 3, 2019 | ESR Branch | ✅ |
2020-Present: 4-Week Release Cycle
| Version | Release Date | End of Support | Key Features | ESR Status |
|---|---|---|---|---|
| 69.0~77.0 | September 2019~June 2020 | 4-6 weeks after each | 4-week transition | |
| 78.0 | June 30, 2020 | July 28, 2020 | ESR Branch | ✅ |
| 79.0~90.0 | July 2020~July 2021 | 4 weeks after each | Stable 4-week cycle | |
| 91.0 | August 10, 2021 | September 7, 2021 | ESR Branch | ✅ |
| 92.0~101.0 | September 2021~May 2022 | 4 weeks after each | Privacy enhancements | |
| 102.0 | June 28, 2022 | July 26, 2022 | ESR Branch | ✅ |
| 103.0~114.0 | July 2022~June 2023 | 4 weeks after each | AI preparation | |
| 115.0 | July 4, 2023 | August 1, 2023 | ESR Branch | ✅ |
| 116.0~127.0 | August 2023~June 2024 | 4 weeks after each | AI integration | |
| 128.0 | July 9, 2024 | August 6, 2024 | Current ESR | ✅ |
| 129.0~142.0 | August 2024~August 2025 | 4 weeks after each | End of Life | |
| 143.0 | September 16, 2025 | October 14, 2025 | Current Latest |
5. Scheduled Firefox Release Calendar (H2 2025~2026)
Based on Mozilla’s official release calendar:
| Version | Beta Start | Release Date | End of Support | Release Manager | ESR Version |
|---|---|---|---|---|---|
| 144 | September 15, 2025 | October 14, 2025 | November 11, 2025 | Donal | 140.4 |
| 145 | October 13, 2025 | November 11, 2025 | December 9, 2025 | Pascal | 140.5 |
| 146 | November 10, 2025 | December 9, 2025 | January 13, 2026 | Dianna | 140.6 |
| 147 | December 8, 2025 | January 13, 2026 | February 10, 2026 | Ryan | 140.7 |
Important: 32-bit x86 Linux support ends with Firefox 144.
6. Complete Firefox ESR Schedule
ESR versions are supported for approximately 54 weeks (1 year) and are primarily used in enterprise environments.
Complete ESR Version Support Schedule
| ESR Version | Base Version | Release Date | End of Support | Support Period | Status |
|---|---|---|---|---|---|
| 10.0 | Firefox 10 | January 31, 2012 | January 8, 2013 | 54 weeks | End of Life |
| 17.0 | Firefox 17 | November 20, 2012 | October 29, 2013 | 49 weeks | End of Life |
| 24.0 | Firefox 24 | September 17, 2013 | December 1, 2014 | 62 weeks | End of Life |
| 31.0 | Firefox 31 | July 22, 2014 | March 8, 2016 | 85 weeks | End of Life |
| 38.0 | Firefox 38 | May 12, 2015 | August 2, 2016 | 64 weeks | End of Life |
| 45.0 | Firefox 45 | March 8, 2016 | June 13, 2017 | 66 weeks | End of Life |
| 52.0 | Firefox 52 | March 7, 2017 | September 5, 2018 | 78 weeks | End of Life |
| 60.0 | Firefox 60 | May 9, 2018 | October 22, 2019 | 75 weeks | End of Life |
| 68.0 | Firefox 68 | July 9, 2019 | October 5, 2021 | 117 weeks | End of Life |
| 78.0 | Firefox 78 | June 30, 2020 | October 5, 2021 | 66 weeks | End of Life |
| 91.0 | Firefox 91 | August 10, 2021 | August 23, 2022 | 54 weeks | End of Life |
| 102.0 | Firefox 102 | June 28, 2022 | September 26, 2023 | 65 weeks | End of Life |
| 115.0 | Firefox 115 | July 4, 2023 | March 2026 | 148+ weeks | Legacy OS Support |
| 128.0 | Firefox 128 | July 9, 2024 | September 16, 2026 | 118 weeks | Current ESR |
ESR 115 Extended Support Details
| Platform | End of Support | Extension Reason | Reevaluation |
|---|---|---|---|
| Windows 7 | March 2026 | 6.7% user base | February 2026 |
| Windows 8/8.1 | March 2026 | Legacy system support | February 2026 |
| macOS 10.12-10.14 | March 2026 | Hardware limitations | February 2026 |
7. Platform-Specific End-of-Life Notices
32-bit Linux Support Discontinuation
Mozilla announced in September 2025 that 32-bit x86 Linux support will end with Firefox 144. Firefox 145 and later will not provide 32-bit Linux builds.
Current 32-bit Linux users should transition to 64-bit operating systems.
macOS Support Policy
Firefox supports only the latest 3 macOS versions, following Apple’s support cycle. Legacy macOS users can receive security updates through ESR 115 until March 2026.
8. Firefox Version Check and Update Methods
Checking Current Firefox Version
- Via Menu
- Firefox Menu (☰) → Help → About Firefox
- Or enter
about:supportin the address bar
- Keyboard Shortcuts
- Windows/Linux:
Alt + H→A - macOS:
Command + ,(check in Preferences)
- Windows/Linux:
- Command Line (for developers)
firefox --version
Configuring Automatic Updates
- Access Settings
- Firefox Menu (☰) → Settings → General
- Or enter
about:preferencesin the address bar
- Firefox Updates Section
- ✅ Automatically install updates (recommended)
- ⚪ Check for updates but let you choose to install them
- ⚪ Never check for updates (not recommended)
9. Security Risks and Mitigation Strategies
Security Risks of End-of-Life Versions
Using end-of-life Firefox versions exposes users to:
- No security patches for newly discovered vulnerabilities
- Reduced protection against malicious websites and phishing
- Compatibility issues with modern web standards
Currently Secure Versions
Safe to use:
- ✅ Firefox 143.0 (recommended for general users)
- ✅ ESR 128.14.0 (enterprise/stability focused)
- ✅ ESR 115.23.0 (Windows 7-8.1, macOS 10.12-10.14 only)
Immediate update required:
- ❌ Firefox 142.0 and earlier versions
- ❌ ESR 115 (except on legacy OS)
- ❌ ESR 102 and earlier versions
Recommended Actions
- Enable automatic updates: Settings → General → Firefox Updates
- Regular version checks: Verify current version monthly
- Legacy OS users: Consider OS upgrades when hardware permits
10. Enterprise Firefox Version Management
ESR Recommended Scenarios
- Large organizations requiring unified browser environments
- Web-based business systems needing compatibility validation time
- Environments avoiding frequent browser changes
Update Planning Guidelines
ESR migrations occur automatically after the new ESR’s .3.0 release. For example, ESR 115 to ESR 128 migration happens after ESR 128.3.0 release.
Organizations should conduct compatibility testing in advance of these migration patterns.
Transitioning to ESR
- Backup current Firefox (bookmarks, settings, etc.)
- Visit Mozilla ESR download page: https://www.mozilla.org/firefox/organizations/
- Remove existing Firefox and install ESR
- Restore profile (if needed)
Note: Transitioning from standard Firefox to ESR may remove some latest features.
11. Frequently Asked Questions
Q: How do I disable Firefox automatic updates?
A: Go to Settings → General → Firefox Updates and select “Check for updates but let you choose to install them.”
Q: Should I choose ESR or standard Firefox?
A: For general users, standard Firefox provides faster access to new features and security patches. Choose ESR for stability-critical or enterprise environments.
Q: When should I update if using an end-of-life version?
A: Update at least 1-2 weeks before the end-of-life date to avoid emergency security situations.
Q: Can I continue using Firefox on legacy operating systems?
A: Windows 7-8.1 and macOS 10.12-10.14 can receive security updates through ESR 115 until March 2026. However, OS upgrades are recommended when possible.
Q: Can I continue using Firefox on 32-bit Linux?
A: 32-bit Linux support ends with Firefox 144 (October 2025). Consider transitioning to 64-bit systems or alternative browsers.
Understanding Firefox’s complete version support policy and updating at appropriate times ensures a secure and optimal browsing environment. Mozilla’s official policy releases standard Firefox every 4 weeks and ESR approximately every 54 weeks. Regularly monitor Mozilla’s official release information, Firefox end-of-life schedule, and Mozilla release calendar for the latest updates.
For enterprise Firefox deployments, consult Mozilla’s Enterprise Firefox guide to establish systematic update planning. 🙂