Mozilla on Tuesday officially launched Firefox 20 for Windows, Mac, Linux, and Android. The improvements include per-window private browsing, a new download manager in the Firefox toolbar, and the ability to close hanging plugins separately.

The new desktop version was available yesterday on the organization’s FTP servers last night, but that was just the initial release of the installers. Firefox 20 has now officially been made available over on Firefox.com and all users of old Firefox versions should be able to upgrade to it automatically. As always, the Android version is trickling out slowly on the official Google Play Store.

For those who don’t know, private browsing lets you browse the Internet without saving any information about which sites and pages you’ve visited (private browsing data does not show up in your Awesome Bar History or Awesome Screen shortcuts). Other browsers have it too (Incognito for Chrome and InPrivate for IE), and it’s often simply referred to as “porn mode.”

Desktop

Firefox has had private browsing for a long time, but it has always required you to open a separate private browsing window. Now you can do so without closing or changing your current browsing session. Mozilla suggests two use cases for this: shopping for a birthday gift in a private window or checking multiple email accounts simultaneously.

Mozilla’s browser has also received a new download manager in the Firefox toolbar, letting you monitor, view, and locate downloaded files without having to switch to another window. The ability to close plugins separately is a nice touch for stability, as it means it won’t (or at least shouldn’t) hang the whole browser.

There are naturally other Firefox 20 features worth noting; here’s the official changelog:

FIXED: Security fixes can be found here.

NEW: Per-window Private Browsing. Learn more.

NEW: New download experience. Learn more.

NEW: Ability to close hanging plugins, without the browser hanging.

CHANGED: Continued performance improvements around common browser tasks (page loads, downloads, shutdown, etc.).

DEVELOPER: Continued implementation of draft ECMAScript 6 – clear() and Math.imul.

DEVELOPER: New JavaScript Profiler tool.

HTML5: getUserMedia implemented for web access to the user’s camera and microphone (with user permission).

HTML5: <canvas> now supports blend modes.

HTML5: Various <audio> and <video> improvements.

FIXED: Details button on Crash Reporter

(793972).

(793972). FIXED: Unity plugin doesn’t display in HiDPI mode

(829284).

If you’re a Web developer, you should probably check out Firefox 20 for developers.

Android

Mozilla has also managed to bring private browsing on a per tab basis to Firefox for Android. The mobile browser allows you to open a new private browsing tab during your current browsing session, so you can switch between private and standard tabs within the same browsing session. In other words, you don’t have to relaunch the Firefox app every time.

The Android release has also received customizable shortcuts on the home screen. This means you can now customize the shortcut images on the home screen with your favorite or most frequently visited sites by simply tapping and holding your top sites, and then choosing “pin” from the drop-down menu.

Firefox for Android has also added support for additional devices running on a less powerful processor architecture: ARMv6. This includes popular phones like Samsung Galaxy Next, HTC Aria, HTC Legend, Samsung Dart, Samsung Galaxy Pop, and the Samsung Galaxy Q. Mozilla says with this release it now offers its browser on almost 50 million more phones.

Here’s the full Android changelog:

FIXED: Security fixes can be found here.

NEW: Per-tab private browsing.

NEW: Gingerbread and Honeycomb support for H.264/AAC/MP3 hardware decoders.

NEW: Top Sites in about:home are now customizable.

CHANGED: The ‘Quit’ menu item has been removed from Firefox versions running on ICS and higher to follow Android convention. When done browsing just tap Home or Back. Use the QuitNow add-on if you want more control.

CHANGED: System requirements have been lowered to 384MB of RAM and QVGA displays.

DEVELOPER: Continued implementation of draft ECMAScript 6 – clear() and Math.imul.

HTML5: <canvas> now supports blend modes.

HTML5: Various <audio> and <video> improvements.

FIXED: Hide virtual keyboard when bookmarks list is opened

(808408).

(808408). FIXED: Black area near tabs button after the URL bar is animated

(817828).

(817828). FIXED: Tablets – home tab thumbnails may appear cut off

(824483).

If you’re having difficulty keeping track, don’t worry. Firefox 21 will be out in May.

Top Image Credit: Robert Linder

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