Firefox 148 Adds Master Switch for AI Features Amid User Backlash

Mozilla has released Firefox 148 alongside Thunderbird 148, introducing a long-awaited global toggle switch that allows users to completely disable all AI-powered features in the browser. The move comes after months of user complaints about the browser's increasing reliance on large language models (LLMs) and the associated performance impacts.

The new AI control panel, accessible through Firefox's settings, provides a master switch labeled "Block AI enhancements" that prevents users from seeing new or current AI features, along with pop-ups promoting them. Below this main toggle are five individual switches for specific LLM-based functionalities:

• On-device AI Translations
• Image alt text in Firefox PDF viewer
• Tab group suggestions
• Key points in link previews
• Chatbot in sidebar

This granular control allows users to maintain useful features like local translation while disabling other AI-powered additions they find intrusive or unnecessary.

The AI Feature Controversy

The saga of AI integration in Firefox began with version 141 in July 2025, which introduced an embedded LLM bot to automatically generate names for tab groups. This seemingly innocuous feature sparked immediate criticism from users who questioned both the necessity and the resource consumption of such functionality.

Within weeks, users began reporting significant CPU usage increases, with Firefox processes consuming excessive system resources. Despite these complaints, Mozilla continued expanding AI features, adding bot-powered link summaries in subsequent versions and promising an "AI window" feature that met with widespread user disapproval.

Performance and Security Improvements

Beyond the AI toggle, Firefox 148 includes several important updates. The browser now features improved HTML sanitization to better block cross-site scripting attacks, addressing a critical security concern for web users.

Users can now disable Mozilla's telemetry collection while still receiving what the company calls "Remote Improvements" - essentially notifications about new browser versions and updates. This change provides more privacy-conscious users with greater control over their data while maintaining access to essential browser functionality.

For Windows 10 users, particularly those running the Windows 10 LTSC (Long-Term Servicing Channel) edition, Firefox Backup can now save session details even without Firefox Sync enabled. This enhancement is particularly valuable for enterprise users and those who prefer not to use Mozilla's synchronization service.

Thunderbird 148 Updates

The companion release, Thunderbird 148, focuses primarily on authentication improvements and security fixes. The email client now supports NTLM (New Technology LAN Manager) authentication for Microsoft Exchange servers, addressing compatibility needs for organizations using older Windows-based network infrastructure.

Additionally, Thunderbird 148 switches authentication methods for Yahoo, AT&T, and AOL accounts to use PKCE (Proof Key for Code Exchange) authentication. Users with accounts on these services may need to re-authenticate after updating.

The email client also includes improved accessibility features, better folder tree handling, enhanced management of favorite destinations, and approximately 50 security fixes.

User Choice and Browser Philosophy

The introduction of the global AI toggle represents a significant shift in Mozilla's approach to feature deployment. Rather than forcing users to accept new AI-powered functionality, the company has acknowledged the demand for user choice and control over browser capabilities.

This change aligns with Mozilla's historical commitment to user privacy and control, distinguishing Firefox from competitors that have been more aggressive in pushing AI features to users without opt-out mechanisms.

For users who remain uncomfortable with any AI integration, Firefox forks like Waterfox continue to offer alternatives without telemetry or AI features. Waterfox's lack of telemetry notably protected its users from the "Foxstuck" bug in 2022, demonstrating the security benefits of minimal data collection.

Firefox 148 is available now through the standard update mechanism, with the AI toggle switch immediately accessible to all users who wish to modify their browser's AI feature set.