Firefox 155 Launches With AI Smart Window and Faster Page Loads

Mozilla released Firefox 155 on September 1, 2026, marking the first update under a new, accelerated two-week release cycle. The update introduces significant performance enhancements, expands its AI-powered Smart Window feature to more users, and addresses several long-standing bugs, particularly for Linux users. The most prominent user-facing feature is the broader rollout of Smart Window, an optional AI browsing mode. The feature is now available to users in the United States, Canada, and France.