Mozilla launched Firefox 42 for Windows, Mac, Linux, and Android. Notable additions to the browser include tracking protection, tab audio indicators, and background link opening on Android.

Firefox 42 for the desktop is available for download now on, and all existing users should be able to upgrade to it automatically. As always, the Android version is trickling out slowly on Google Play.

Mozilla doesn’t break out the exact numbers for Firefox, though the company does say “half a billion people around the world” use the browser. In other words, it’s a major platform that web developers target — even in a world increasingly dominated by mobile apps.

The new private browsing mode goes further than just not saving your browsing history  — the added tracking protection means Firefox also blocks website elements (ads, analytics trackers, and social share buttons) that could track you while you’re surfing the web, and it works on all four platforms. The feature is almost like a built-in ad blocker, though it’s really closer to browser add-ons like Ghostery and Privacy Badger because ads that don’t track you are allowed through.

The new private browsing mode also has a Control Center with all of Firefox’s site security and privacy controls. Since some web pages may appear broken when elements that track behavior are blocked, Control Center lets you turn off Tracking Protection for a particular site.

To try it out, click the hamburger menu button (three lines in the top right corner), click the New Private Window icon to launch a Private Browsing session, and you’ll see a screen that confirms Tracking Protection is on. Now all you have to do is browse the Web as usual.

That’s for desktop browsers. On Android, tap the Firefox Menu button (below the screen on some devices, or at the top-right corner of the browser on others) and then tap New Private Tab.

In short, Mozilla is attempting to take browser privacy to the next level. The company is seeing a lot of support from Firefox users, especially those who believed private browsing was already protecting them from third-party tracking on the Internet.

There are also potential performance improvements. A recent paper found that with tracking protection enabled, the top 200 news sites saw a 44 percent median reduction in page load time and 39 percent reduction in data usage.

In August, Mozilla added the new experimental feature to Firefox Developer Edition for Windows, Mac, and Linux, as well as the Firefox Aurora channel on Android. In September, the feature arrived in the beta channel, and now it’s finally available for all users.