10 Key Updates in Firefox 151: From Firefox Home to PDF Merging

Firefox 151 arrives on May 19, 2026, bringing subtle but meaningful changes. Mozilla’s open-source browser continues to evolve with a refreshed new tab page, now called Firefox Home, and the long-awaited ability to merge PDFs directly in the browser. Read on for the ten most important things you need to know about this release.

1. Firefox Home Replaces the New Tab Page

The new tab page has been rebranded as Firefox Home. While the core functionality remains similar, this name change hints at a more personalized start experience in future updates. The visual tweaks are minor but noticeable, including a softer color palette and refined spacing. The page still displays your top sites, recent activity, and recommended stories, but the overall feel is cleaner. Mozilla promises deeper integration with your browsing habits down the line, making Firefox Home a true dashboard for your online life.

2. Rounded Search Bar Inspired by Nova

Firefox 151 introduces a pill-shaped search bar that draws from the upcoming Nova redesign. This rounded look is more modern and consistent with current design trends. The search bar now sits flush with the page background, giving it a floating appearance. It’s a small change, but it makes the interface feel more polished and less cluttered. If you’ve been using the developer edition or nightly builds, you may have seen this shape before—now it’s hitting the stable channel.

3. Search Bar No Longer Sticky on Scroll

Previously, the search bar stayed pinned to the top of the new tab page as you scrolled through stories. In Firefox 151, that sticky behavior is gone. The search bar now moves with the content, disappearing when you scroll down. This change reduces visual distraction and gives you more screen real estate for browsing. However, if you frequently search from the new tab page, you’ll need to scroll back up or use the keyboard shortcut (Ctrl+L or Cmd+L). It’s a trade-off that some may appreciate.

4. Stories Section Remains Unchanged

The Stories section, which shows recommended articles from Pocket, stays exactly as it was. Mozilla has not altered its layout, content sources, or personalization options. Stories continue to appear in a grid below the search bar, with topics like technology, culture, and science. This stability is good news for regular readers. The only slight modification is the placement of the “follow” button, which has moved to a new location (see next item).

5. Follow Button Now a Plus-Sign Icon

To follow a topic in Stories, you previously clicked a dedicated button. In Firefox 151, that button is replaced by a plus-sign icon positioned to the left of the section header. It’s a minimalist change that saves space and aligns with standard UI patterns. Clicking the icon opens a small menu to select topics you want to see more of. While functionally identical, the new placement may take a moment to locate. Once you do, it works as expected.

6. PDF Merging Is Finally Here

One of the most requested features, PDF merging, debuts in Firefox 151. You can now combine multiple PDF files into a single document without leaving the browser. Simply open a PDF, click the new “Merge” button in the toolbar, select additional files, and arrange them in your preferred order. The merged file can be downloaded or shared instantly. This feature works entirely offline and respects your privacy—no files are sent to any server. It’s a huge time-saver for students, professionals, and anyone handling documents.

7. Performance Improvements Under the Hood

Firefox 151 includes optimizations that make the browser feel snappier. Page loading times have improved by up to 12% on complex sites, thanks to better caching algorithms and JavaScript engine tweaks. Memory usage has also decreased, especially when multiple tabs are open. The browser now handles background tabs more efficiently, reducing resource drain. These changes may not be visible, but you’ll notice smoother scrolling and faster transitions when switching between tasks.

8. Security Fixes and Privacy Updates

Version 151 patches several security vulnerabilities, including a critical flaw in the rendering engine that could allow remote code execution. Mozilla has also enhanced Enhanced Tracking Protection with new fingerprinting countermeasures. Additionally, the browser now blocks more cryptominers by default. For privacy-conscious users, the Total Cookie Protection feature has been extended to cover all third-party cookies. These updates ensure that Firefox remains one of the most secure browsers available.

9. Better Sync and Tab Management

Syncing your browsing data across devices gets a boost in Firefox 151. The Send Tab feature now works more reliably, especially on slower networks. You can also view synced tabs from your phone directly in the desktop sidebar without needing to open a separate window. Tab grouping has been refined: you can now collapse or expand entire groups with a single click. These improvements make organizing your workflow across devices much smoother.

10. A Glimpse of the Nova Redesign

Firefox 151 serves as a stepping stone to the Nova redesign, Mozilla’s upcoming visual overhaul. The rounded search bar, softer shadows, and streamlined icons preview what’s to come. Nova promises a complete refresh of the interface with a focus on clarity and ease of use. By introducing these elements gradually, Mozilla lets users adapt without a jarring change. Expect more Nova elements in subsequent releases, including a revamped settings menu and toolbar.

Firefox 151 brings a mix of visible tweaks and behind-the-scenes improvements. From the renamed Firefox Home to the practical PDF merging tool, this update shows Mozilla’s commitment to evolving the browser for modern needs. Whether you’re a design enthusiast or a productivity seeker, there’s something to appreciate. Upgrade today to experience the changes firsthand.