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:

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)

Rapid Release Era (5.0~Present)

2011-2015: 6-Week Release Cycle

2015-2019: 6-8 Week Release Cycle

2020-Present: 4-Week Release Cycle

5. Scheduled Firefox Release Calendar (H2 2025~2026)

Based on Mozilla’s official release calendar:

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 115 Extended Support Details

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

1. Via Menu
   • Firefox Menu (☰) → Help → About Firefox
   • Or enter about:support in the address bar
2. Keyboard Shortcuts
   • Windows/Linux: Alt + H → A
   • macOS: Command + , (check in Preferences)
3. Command Line (for developers)

   firefox --version
   

Configuring Automatic Updates

1. Access Settings
   • Firefox Menu (☰) → Settings → General
   • Or enter about:preferences in the address bar
2. 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

1. Enable automatic updates: Settings → General → Firefox Updates
2. Regular version checks: Verify current version monthly
3. 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

1. Backup current Firefox (bookmarks, settings, etc.)
2. Visit Mozilla ESR download page: https://www.mozilla.org/firefox/organizations/
3. Remove existing Firefox and install ESR
4. 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. 🙂