Firefox Beta 22.0

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Personal
Library

Make your browser as efficient as you can imagine. Your browsing history (all the websites you’ve seen) and your bookmarks (all the websites you’ve saved) are archived in the Library, where they can be easily searched and organized. You can also save your frequent searches in dynamic smart folders that automatically update as your bookmark list and history grow.
Tags

Label a site with names or categories that are meaningful to you. For example, you can label the site www.bbc.co.uk with the “news” tag as well as the “foreign investments” tag, plus give www.nytimes.com the “news” tag, too. When you enter “news” into the location bar, both sites will be shown as results. A single site can have multiple tags, and there’s no limit to the number of tags you can create. You may not remember the exact name of a site, but with a tag, you’ll be able to find it in a way that makes sense to you.
Smart Location Bar
Smart Location Bar screenshot

A quick way to get to the sites you love—even the ones with addresses you only vaguely remember. The new Firefox 3 location bar learns as you use it—it’s so highly evolved that we like to call it the “Awesome Bar”. Over time, it adapts to your preferences and offers better fitting matches. Type in a term and the autocomplete function includes possible matching sites from your browsing history, as well as sites you’ve bookmarked and tagged in a drop down. For example, you could enter the tag: “investments” to find “www.fool.com”. Matched terms are highlighted, making the list of results easy to scan.
One-Click Bookmarking
One-Click Bookmarking screenshot

Manage your bookmarks a lot or a little. One click on the star icon at the end of the location bar bookmarks a site. Two clicks and you can choose where to save it and whether to tag it. File bookmarked sites in easy-to-access folders and organize according to theme (like “job search” or “favorite shopping”). Find your bookmarked sites in a flash by entering the tag, page or bookmark name into the location bar. The more you use your tags and bookmark names in the location bar, the more the system will adapt to your preferences.
Smart Bookmark Folders

These dynamic folders give you easy access to your favorite sites and can be placed in your Bookmarks menu or Bookmarks toolbar. We’ve included some for you as defaults, including one that shows you the sites you visit most frequently (create your own by saving your searches in the Library).
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Security & Privacy
Instant Web Site ID screenshot
Instant Web Site ID

Want to be extra sure about a site’s legitimacy before you make a purchase? Click on a site favicon for an instant identity overview. Another click digs deeper: how many times have you visited? Are your passwords saved? Check up on suspicious sites, avoid Web forgeries and make sure a site is what it claims to be.
Anti-Malware

Firefox 3 protects you from viruses, worms, trojan horses and spyware. If you accidentally access an attack site, you’ll receive a full-sized browser message as a warning. A continuously updated list of attack-sites tells us when to stop you from browsing, so there’s nothing for you to update or maintain.
Anti-Malware screenshot
Anti-Phishing

Shop and do business safely on the Internet. Firefox gets a fresh update of web forgery sites 48 times in a day, so if you try to visit a fraudulent site that’s pretending to be a site you trust (like your bank), a browser message—big as life—will stop you.
Parental Controls

Enforce parental control settings you’ve entered on Windows Vista with Firefox 3—stop unwanted downloads and more. Firefox’s intuitive design keeps you from second-guessing your setup.
Anti-Virus Software

Firefox 3 integrates elegantly with your antivirus software. When you download a file, your computer’s antivirus program automatically checks it to protect you against viruses and other malware, which could otherwise attack your computer. [available in Windows only]
Add-ons

Firefox looks for a secure connection before installing or updating add-ons, 3rd party software, and Personas.
Password Manager

We’ve seamlessly integrated this feature into your surfing experience. Choose to “remember” site passwords without intrusive pop-ups. Now you’ll see the “remember password” notification integrated into your view at the top of the site page.
Password Manager screenshot
Clear Private Data

Clear your private data automatically—with just one click or a keyboard shortcut. Your info is gone for good—on your own computer or the one at your local library. It’s that easy.
Customized Security Settings

Control the level of scrutiny you’d like Firefox to give a site and enter exceptions—sites that don’t need the third degree. Customize settings for passwords, cookies, loading images and installing add-ons for a fully empowered Web experience.
Automated Update

Our open-source security strategy lets us find—and fix—security issues in record time, making Firefox the safest way to surf. Install upgrades when you receive automatic notification or wait until you’re ready.
Pop-Up Blocker

Banish pop-ups (and pop-under windows) from your surfing experience once and for all. Or, find a happy medium—choose to view blocked pop-ups or create an “allow” list of sites whose pop-ups you’re okay with seeing.
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Customization
Add-ons Manager screenshot
Add-ons Manager

You can now find and install add-ons directly in your browser. You no longer need to visit the add-ons Web site, simply fire up the new Add-ons Manager. Not sure which add-on is right for you? Ratings, recommendations, descriptions and pictures of the add-ons in action help you make your selection. The fully integrated Add-ons Manager even lets you view, manage and disable third-party add-ons in a few easy clicks.
Over 5,000 ways to customize

The sky’s the limit with a growing library of over 5,000 Firefox Add-ons, little extras you choose to download and install for a browser that works your way. Manage online auctions, upload digital photos, see the weather forecast in a glance and listen to music all from the convenience of your browser. There’s no need to open a new window or tab for each task. Discover add-ons that help you streamline coding and Web development, like Firebug, which lets you look deep into the structure of a web page.
Browser Look & Feel

Dress up your browser as you like it. With themes, choose a darkened control panel reminiscent of a space ship, faux wood paneling, or hundreds of other unique looks to surround your surfing. With Personas, add a simple, lightweight “skin” to your browser in an instant. (Personas is a Mozilla Labs project.)
Beyond Add-ons

Add-ons are the cornerstone of customization, but adapting Firefox to suit your style doesn’t stop there. You can add new search engines, change toolbar preferences, display different sizes, shapes and styles for your browser’s navigation buttons and more. With additional preferences, you can specify a Web mail client, such as Gmail, to open up when you click on an address from a Web page or set up a news reader application for the blogs you encounter.
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Productivity
Platform-Native Look & Feel

The new Firefox looks and feels like home. Think of it as a Firefox who’s really good at making friends. Whether you use Windows Vista, Windows XP, Mac or Linux, the browser seamlessly integrates into your computer’s environment. A native look makes for a flawless interface that never gives you pause.
Feed Reader

You can read feeds using an online Web service, a client-side feed reader or by creating a Firefox Live Bookmark. So there’s no need to comb the Web for the latest news and updates. See the latest headlines in the toolbar or menu and go directly to the articles that catch your eye.
Download Manager screenshot
Download Manager

An all new manager lets you download seamlessly, with even greater security. A pause and resume feature means there’s no need to wait for a download to finish before you disconnect. So, if you’re halfway through the latest White Stripes album and it’s time to catch the bus, just pause and pick up downloading when you get home. The resume function also works if your system crashes or is forced to restart. The manager shows your download progress and lets you search your files by name or the Web address where the download came from.
Spell Checking

A built-in spell checker lets you enter text directly into Web pages— like blog posts and Web-based email—without worrying about typos and misspellings. Work directly with the Web and save yourself a step.
Spell Checking screenshot
Session Restore

If Firefox unexpectedly closes, you don’t have to spend time recovering data or retracing your steps through the Web. If you’re in the middle of typing an email, you’ll pick up where you left off, even down to the last word you typed. Session Restore instantly brings back your windows and tabs, restoring text you entered and any in-progress downloads. Restart the browser without losing your place after you install an add-on or software update.
Full Zoom

Visit your favorite news page and read the caption under the picture—or view the picture itself in a size you can see. An elegant new zoom feature lets you swoop in and see entire web pages. They scale in the way you’d expect them to, with all the elements of a page’s layout expanding equally, so you can zero in on what matters.
Image Loading

If you want to save time and bandwidth, view a site without images. Firefox will remember your setting the next time you view the page.
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Search
Smart Keywords

Search the Web in record time with smart keywords. With a few clicks you can assign keywords to search engines, and then simply enter your key and search words in the location bar. With this feature, typing “book home building” can search Amazon.com, and take you right to books about home building without ever pausing at the homepage.
Search Suggestions screenshot
Search Suggestions

Start typing in the search bar and it will prompt you with a drop down of filled-in suggestions, plus you can use the search bar as a calculator, converter and more.
Integrated Web Search screenshot
Integrated Web Search

Searching the Web is a breeze with the search box inline, just to the right of your location bar. Use the web engine of your choice to search by typing directly into the box. The width is adjustable so you can make it bigger if you need more space.
Hundreds of Search Engines

Access your favorite search engines quickly from the integrated search bar. You can use a new engine for each search, or stick to your favorite. Choose from a preset dropdown list of engines or select “manage search engines” from the same list to browse search engine options offered as add-ons. Check out your choices now.
Find screenshot
Find

The find feature appears in a keystroke. Search for a word or phrase on an open Web page. Highlight text before using the feature and finder opens pre-filled with your selection. See all instances of your search at once, or scroll backwards and forwards through the appearances of the word on the page.
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Tabs
Save on Exit

Now when you open Firefox, your tabs and windows look just like they did when you closed it down. No need to reopen all your windows each time you start a session.
Tabs

At first glance, they look like little labels living above the site you’re currently visiting. But they are a brilliant way to browse multiple sites at once. Simple and easy, you can think of them as the electronic version of a well kept filing cabinet, with the tabs as the dividers and the sites as the content kept in folders. Each new site appears as a new tab (not a new window) and can be accessed in one click.
Tabs screenshot
Reopen Closed Tabs

If you accidentally close a tab, you can reopen it in one click. Just view Recently Closed Tabs in the History menu and select the tab you’d like to reopen.
Drag & Reorder Tabs

Get your sites in order. Simply arrange the order of your tabs by dragging them in one swift move of your mouse.
Smooth Scrolling

Like to have all 20 of your favorite pages open at once? An elegant new feature lets you scroll through tabs easily to see them all and access the one you want quickly.
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Universal Access
Universal Customization

Go beyond translation and experience the web in a way that makes sense to you. Local developers who know what’s best for their community have customized your Firefox browsing experience with local dictionaries, search providers, live bookmarks and Web feeds. Depending on where you live, you’ll see things like BBC headlines tailored to your region or experience features that work with Baidu, the Chinese search engine.
The Language of Firefox

Firefox speaks your language like no other browser on earth. Because the Web is a worldwide resource and we believe that resource belongs to the people, we’ve made our browser available in as many local languages as possible. We have over 40 different translations, from French and Chinese to Finnish and Czech. Find your language.
Emphasis on Accessibility

By minimizing keystrokes, allowing users to zoom in on Web pages and supporting screen readers, Firefox is that much easier to use for those with mobility disabilities and visual impairments.
Improved Text Rendering screenshot
Improved Text Rendering

Read your language as it’s written—more like real life. With a new graphics engine, Arabic, Persian, Punjabi and other script languages now render in a remarkably seamless way.
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Performance
Improved Memory Management

With all new management functions in place, Firefox 3 keeps memory usage under control. The XPCOM cycle collector continuously cleans up unused memory. Plus, hundreds of memory leaks are now remedied.
Faster JavaScript

Firefox now empowers even greater Web development, with JavaScript 1.8—including expression closures, generator expression and array reduce.
Smaller Memory Footprint

Short and sweet, Firefox now uses less of your computer’s memory while it’s running.
Faster Page Load

A redesigned page rendering and layout engine means you see Web pages faster—and in the way they were meant to be seen.
Graphics Engine Improvements

Improved text rendering is just the beginning of the benefits of an all new graphic engine for Firefox 3.
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Standards
Advanced Graphics

You have to see it to believe it. The rendering of text and graphics, including SVG and Canvas, is faster, sharper and more true-to-life than ever before, thanks to our new graphics engine.
Online Application Support

Expand the power of Web-based applications. In the past you’d click on an email address in a Web site and your computer’s default email application would open up to send a message to the linked address—even if you never email through the program. Now you can choose a Web mail clients (like Hotmail, Gmail or Yahoo! Mail) to launch when you click on that email address.
Support for Advanced Web Technologies

Brand new and enhanced functionalities enable Web site authors and developers to create advanced content and applications. Support is now available for CSS, ACID2, MathML, ECMAScript 4, Animated Portable Network Graphics (APNG) and Microformats, to name a few. See the full list of supported technologies.
Color Profile Support

Photographers and photo fans, your view of the Web from Firefox just gets better. You can choose to enable top-of-the-line image display which uses technical data, like the amount of light available and relevant distance information, to render images in an amazing new way.
Offline Browsing

Take your computer offline and still have information at your fingertips. Certain enabled sites may allow applications—like your Web-based email—to stay with you at all times. Many sites are not yet configured to work with this feature. Learn more about what works and what doesn’t.

Software OS: Windows 2000

Distribution:Freeware

Download size:7.42MB

Instant FileName:Firefox Setup 20.0b2.exe

Renewed:May 23, 2013

Statistics counter:267 / 4 / 1 - DoDownload made 29.68 MB download traffic in the current month and 1981.14 MB overall

Cost: free

System specs:Unspecified

Firefox Setup 20.0b2.exe file was thoroughly tested by our system on Apr 1, 2013 by the three antivirus programs and passed. Is absolutely clean, enjoy!
This archive is 100% safe to download and install.
Have a look at the full Firefox Beta 22.0 antivirus scan reports.

User's rating:

Currently 2.33/5
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History updates (Complete changelogs since the listing on this site)

22.0 [05-23-13]

NEW Windows: Firefox now follows display scaling options to render text larger on high-res displays
NEW WebRTC is now enabled by default!
NEW Mac OS X: Download progress in Dock application icon
NEW HTML5 audio/video playback rate can now be changed
NEW Social services management implemented in Add-ons Manager
NEW asm.js optimizations (OdinMonkey) enabled for major performance improvements
CHANGED Improved WebGL rendering performance through asynchronous canvas updates
CHANGED Plain text files displayed within Firefox will now word-wrap
CHANGED For user security, the |Components| object is no longer accessible from web content
CHANGED Improved memory usage and display time when rendering images
CHANGED Pointer Lock API can now be used outside of fullscreen
DEVELOPER CSS3 Flexbox implemented and enabled by default
DEVELOPER New Web Notifications API implemented
DEVELOPER Added clipboardData API for JavaScript access to a user's clipboard
DEVELOPER New built-in font inspector
HTML5 New HTML5 and elements
FIXED Scrolling using some high-resolution-scroll aware touchpads feels slow (829952)

Other versions : 21.0 20.0 19.0 18.0 17.0 4.0rc2 4.0rc1 4.0b12 4.0b11 4.0b10 4.0b9 4.0b8 4.0b7 4.0b6 4.0b5 4.0b4 4.0b3 4.0b2 4.0b1 3.6.7build1 3.6.4build7 3.6.4build5 3.6.4build4 3.6.4build3 3.6.4build1 3.6.3plugin1 3.6rc2 3.6rc1 3.6b5 3.6b4 3.6b3 3.6b2 3.6b1 3.5rc3 3.5rc2 3.5b4

v21.0 [04-05-13]

NEW Enhanced three-state UI for Do Not Track (DNT)
NEW Firefox will suggest how to improve your application startup time if needed
NEW Preliminary implementation of Firefox Health Report (see FAQ)
CHANGED Ability to Restore removed thumbnails on New tab Page
CHANGED Add-ons History API removals in Places
CHANGED CSS -moz-user-select:none selection changed to improve compatibility with -webkit-user-select:none (bugs 816298)
CHANGED Graphics related performance improvements (bugs 809821)
CHANGED Removed E4X support from SpiderMonkey
DEVELOPER Implemented Remote Profiling
DEVELOPER Integrated, Add-on SDK loader and API libraries into Firefox
HTML5 Added support for
element
HTML5 Implemented scoped stylesheets
FIXED Some function keys may not work when pressed (833719)
FIXED Browsing and Download history clearing needs unification to avoid confusion on clearing download history (847627)

v20.0 [02-28-13]

NEW Per-window Private Browsing
NEW New download experience
NEW Ability to close hanging plugins, without the browser hanging
NEW Firefox will offer to reset the Awesomebar search provider, if it has been changed by third-party software or through about:config
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
HTML5 Various
HTML5 getUserMedia implemented for web access to the user's camera and microphone (with user permission)
FIXED Details button on Crash Reporter (793972)
FIXED Unity plugin doesn't display in HiDPI mode (829284)

v19.0 [01-18-13]

NEW Built-in PDF viewer
NEW Firefox will offer to reset the Awesomebar search provider, if it has been changed by third-party software or through about:config
CHANGED Canvas elements can export their content as an image blob using canvas.toBlob()
CHANGED Startup performance improvements (bugs 715402 and 756313)
DEVELOPER Debugger now supports pausing on exceptions and hiding non-enumerable properties
DEVELOPER Remote Web Console is available for connecting to Firefox on Android or Firefox OS (experimental, set devtools.debugger.remote-enabled to true)
DEVELOPER There is now a Browser Debugger available for add-on and browser developers (experimental, set devtools.chrome.enabled to true)
DEVELOPER Web Console CSS links now open in the Style Editor
HTML5 CSS @page is now supported
HTML5 CSS viewport-percentage length units implemented (vh, vw, vmin and vmax)
HTML5 CSS text-transform now supports full-width
FIXED Starting Firefox with -private flag incorrectly claims you are not in Private Browsing mode (802274)

v18.0 [11-30-12]

NEW Support for Retina Display on OS X 10.7 and up
NEW Preliminary support for WebRTC
CHANGED Experience better image quality with our new HTML scaling algorithm
CHANGED Performance improvements around tab switching
DEVELOPER CSS3 Flexbox implemented
DEVELOPER Support for new DOM property window.devicePixelRatio
DEVELOPER Support for @supports added
DEVELOPER Improvement in startup time through smart handling of signed extension certificates
HTML5 Support for W3C touch events impemented, taking the place of MozTouch events
FIXED Disable insecure content loading on HTTPS pages (62178)
FIXED Improved responsiveness for users on proxies (769764)

v17.0 [10-12-12]

NEW Click-to-play blocklisting implemented to prevent vulnerable plugin versions from running without the user's permission (see blog post)
NEW Mac OS X 10.8: Support for Notification Center
CHANGED Updated Awesome Bar experience with larger icons
DEVELOPER JavaScript Maps and Sets are now iterable
DEVELOPER SVG FillPaint and StrokePaint implemented
DEVELOPER Improvements that make the Web Console, Debugger and Developer Toolbar faster and easier to use
DEVELOPER New Markup panel in the Page Inspector allows easy editing of the DOM
HTML5 Sandbox attribute for iframes implemented, enabling increased security
FIXED Over twenty performance improvements, including fixes around the New Tab page
FIXED Pointer lock doesn't work in web apps (769150)
FIXED Page scrolling on sites with fixed headers (780345)

v4.0rc2 [03-20-11]

Blacklisted a few invalid HTTPS certificates
Updated localizations for 29 locales
Added Vietnamese localization, bringing the total languages available in Firefox 4 to 83

As well as these features from previous Firefox 4 Betas:

Support for the proposed Do Not Track ("DNT") header
Connection status messages are now shown in a small overlay
WebGL is enabled on all platforms, but, like for other hardware acceleration features, many buggy drivers or driver versions are blocked
The default homepage design has been refreshed
Firefox no longer switches into offline mode automatically
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0rc1 [03-11-11]

General stability, performance, and compatibility improvements
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 RC is available in 79 languages
Support for the proposed Do Not Track ("DNT") header
Connection status messages are now shown in a small overlay
WebGL is enabled on all platforms, but, like for other hardware acceleration features, many buggy drivers or driver versions are blocked
The default homepage design has been refreshed
Firefox no longer switches into offline mode automatically
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b12 [02-27-11]

Increased performance while viewing Flash content
Improved plugin compatibility with hardware acceleration enabled
Hovering over links now displays the URL at the bottom of the window rather than in the location bar
General stability, performance, and compatibility improvements
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 77 languages
Support for the proposed Do Not Track ("DNT") header
Connection status messages are now shown in a small overlay
WebGL has been re-enabled on Linux
The default homepage design has been refreshed
Firefox no longer switches into offline mode automatically
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Speed, functionality, and compatibility improvements to WebGL
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b11 [02-09-11]

Support for the proposed Do Not Track ("DNT") header
Connection status messages are now shown in a small overlay
WebGL has been re-enabled on Linux
The default homepage design has been refreshed
Firefox no longer switches into offline mode automatically
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 76 languages
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Speed, functionality, and compatibility improvements to WebGL
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b10 [01-28-11]

Compatibilty and stability improvements when using Adobe Flash on Mac OS X
Improvements in memory usage
Support for a graphics driver blacklist to improve stability
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 76 languages
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Speed, functionality, and compatibility improvements to WebGL
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b9 [01-15-11]

Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance
Per-compartment garbage collection is now enabled, reducing work done during complex animations
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 76 languages
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Speed, functionality, and compatibility improvements to WebGL
Additional polish for the Firefox Add-ons Manager
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included but disabled by default at this time
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b8 [12-24-10]

The Firefox Sync setup experience has been greatly improved across desktop and mobile devices
Speed, functionality, and compatibility improvements to WebGL
Additional polish for the Firefox Add-ons Manager
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 69 languages
Uses JägerMonkey, a new, faster JavaScript engine
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included but disabled by default at this time
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b7 [11-11-10]

Uses JägerMonkey, a new, faster JavaScript engine
WebGL is enabled by default on Windows and Mac OS X. WebGL support requires an OpenGL-capable graphics card. Support for other graphics cards on Windows (specifically Intel GPUs) and Linux will be coming in a future beta
Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X
Improved web typography using OpenType with support for ligatures, kerning and font variants
HTML5 Forms API makes web based forms easier to implement and validate
See the complete changelist from the previous beta

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 57 languages
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL
Firefox Sync is now included by default
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped
An experimental API is included to provide more efficient Javascript animations
Firefox now supports the HTML5 video "buffered" property
Tabs are now on top by default on Windows, Mac OS X, and Linux
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu
Web developers can animate content using CSS Transitions
Responsiveness and scrolling improvements from the new retained layers layout system
JavaScript speed improvements due to engine optimizations
Changes to how XPCOM components are registered in order to help startup time and process separation
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions
The stop and reload buttons have been merged into a single button on Windows, Mac OS X, and Linux
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like)
Crash protection for Windows, Linux, and Mac OS X when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins
CSS Transitions are partially supported
Full WebGL support is included but disabled by default at this time
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently
Native support for the HD HTML5 WebM video format
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b6 [09-16-10]

Fixed a stability issue affecting Windows users.
Fixed an issue causing rendering errors with plugins
See the complete changelist from the previous beta.

As well as these features from previous Firefox 4 Betas:

Firefox 4 Beta is available in 39 languages.
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL.
Firefox Sync is now included by default.
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped.
An experimental API is included to provide more efficient Javascript animations.
Firefox now supports the HTML5 video "buffered" property.
Tabs are now on top by default on Windows and OSX - Linux will be changing when the theme has been modified to support the change.
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu.
Web developers can animate content using CSS Transitions.
Responsiveness and scrolling improvements from the new retained layers layout system.
JavaScript speed improvements due to engine optimizations.
Changes to how XPCOM components are registered in order to help startup time and process separation.
You can search for and switch to already open tabs in the Smart Location Bar.
New Addons Manager and extension management API (UI will be changed before final release).
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.
Web authors can now get touch events from Firefox users on Windows 7 machines.
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b5 [09-08-10]

Firefox 4 Beta 5 is available in 39 languages.
Support for the new proposed Audio Data API
Direct2D Hardware Acceleration is now on by default for Windows 7 users
Firefox button has a new look for Windows Vista and Windows 7 users
Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL.
See the complete changelist from the previous beta.

As well as these features from previous Firefox 4 Betas:

Firefox Sync is now included by default.
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped.
An experimental API is included to provide more efficient Javascript animations.
Firefox now supports the HTML5 video "buffered" property.
Tabs are now on top by default on Windows and OSX - Linux will be changing when the theme has been modified to support the change.
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu.
Web developers can animate content using CSS Transitions.
Responsiveness and scrolling improvements from the new retained layers layout system.
JavaScript speed improvements due to engine optimizations.
Changes to how XPCOM components are registered in order to help startup time and process separation.
You can search for and switch to already open tabs in the Smart Location Bar.
New Addons Manager and extension management API (UI will be changed before final release).
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.
Web authors can now get touch events from Firefox users on Windows 7 machines.
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b4 [08-29-10]

Firefox 4 Beta 4 is available in 39 languages.
Firefox Sync is now included by default.
A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped.
An experimental API is included to provide more efficient Javascript animations.
Firefox now supports the HTML5 video "buffered" property.
See the complete changelist from the previous beta.

As well as these features from previous Firefox 4 Betas:

Tabs are now on top by default on Windows and OSX - Linux will be changing when the theme has been modified to support the change.
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu.
Web developers can animate content using CSS Transitions.
Responsiveness and scrolling improvements from the new retained layers layout system.
JavaScript speed improvements due to engine optimizations.
Changes to how XPCOM components are registered in order to help startup time and process separation.
You can search for and switch to already open tabs in the Smart Location Bar.
New Addons Manager and extension management API (UI will be changed before final release).
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.
Web authors can now get touch events from Firefox users on Windows 7 machines.
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b3 [08-12-10]

Firefox 4 Beta 3 is available in 34 languages.
Web authors can now get touch events from Firefox users on Windows 7 machines.
A new way of representing values in JavaScript that allows Firefox to execute heavy, numeric code (used for things like graphics and animations) more efficiently.
See the complete changelist from the previous beta.

As well as these features from previous Firefox 4 Betas:

Tabs are now on top by default on Windows and OSX - Linux will be changing when the theme has been modified to support the change.
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu.
Web developers can animate content using CSS Transitions.
Responsiveness and scrolling improvements from the new retained layers layout system.
JavaScript speed improvements due to engine optimizations.
Changes to how XPCOM components are registered in order to help startup time and process separation.
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b2 [08-01-10]

Firefox 4 Beta 2 is available in 24 languages.
Tabs are now on top by default on Windows and OSX - Linux will be changing when the theme has been modified to support the change.
You can turn any tab into an "App Tab" by right-clicking on it and selecting "Make into App Tab" from the context menu.
Web developers can animate content using CSS Transitions.
Responsiveness and scrolling improvements from the new retained layers layout system.
JavaScript speed improvements due to engine optimizations.
Changes to how XPCOM components are registered in order to help startup time and process separation.
See the complete changelist from the previous beta.

As well as these features from previous Firefox 4 Betas:

You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v4.0b1 [07-10-10]

Tabs are now on top by default on Windows only - OSX and Linux will be changing when the theme has been modified to support the change.
On Windows Vista and Windows 7 the menu bar has been replaced with the Firefox button.
You can search for and switch to already open tabs in the Smart Location Bar
New Addons Manager and extension management API (UI will be changed before final release)
Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like).
Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
CSS Transitions are partially supported.
Full WebGL support is included but disabled by default at this time.
Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
Native support for the HD HTML5 WebM video format.
An experimental Direct2D rendering backend is available on Windows, turned off by default.
Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
Web developers can update the URL field without reloading the page using HTML History APIs.
More responsive page rendering using lazy frame construction.
Link history lookup is done asynchronously to provide better responsiveness during pageload.
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history.
New HTML5 parser.
Support for more HTML5 form controls.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6.7build1 [07-04-10]

Firefox 3.6.7 fixes the following issues found in previous versions of Firefox 3.6:

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.6 release notes for a list of changes in the previous version.

v3.6.4build7 [07-01-10]

Firefox 3.6.4 provides uninterrupted browsing for Windows and Linux users when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins. If a plugin crashes or freezes, it will not affect the rest of Firefox. You will be able to reload the page to restart the plugin and try again. Firefox 3.6.4 also fixes the following issues found in previous versions of Firefox 3.6:

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.3 release notes for a list of changes in the previous version.

v3.6.4build5 [05-27-10]

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.3 release notes for a list of changes in the previous version.

v3.6.4build4 [05-17-10]

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.3 release notes for a list of changes in the previous version.

v3.6.4build3 [05-07-10]

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.3 release notes for a list of changes in the previous version.

v3.6.4build1 [04-22-10]

Fixed several security issues.
Fixed several stability issues.

Please see the complete list of changes in this version. You may also be interested in the Firefox 3.6.3 release notes for a list of changes in the previous version.

v3.6.3plugin1 [04-13-10]

What’s New in Firefox 3.6 Release Candidate 2 Firefox 3.6 Release Candidate is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Maemo.

Made some changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
This release candidate is available in more than 70 languages - get your local version.
More than 70 fixes from the last beta to improve performance, stability, security and features.
The ability to run scripts asynchronously to speed up page load times.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6rc2 [01-18-10]

Made some changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
This release candidate is available in more than 70 languages - get your local version.
More than 70 fixes from the last beta to improve performance, stability, security and features.
The ability to run scripts asynchronously to speed up page load times.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6rc1 [01-10-10]

What’s New in Firefox 3.6 Release Candidate 1 Firefox 3.6 Release Candidate is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

Made some changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
This release candidate is available in more than 70 languages - get your local version.
More than 70 fixes from the last beta to improve performance, stability, security and features.
The ability to run scripts asynchronously to speed up page load times.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6b5 [12-19-09]

What’s New in Firefox 3.6 Beta (revision 5) Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

[NEW] Made some changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
[NEW] This beta is available in more than 70 languages - get your local version.
More than 100 bug fixes from the last beta to improve performance, stability, security and features.
The ability to run scripts asynchronously to speed up page load times.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6b4 [11-27-09]

What’s New in Firefox 3.6 Beta (revision 4) Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

Changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
The ability to run scripts asynchronously to speed up page load times.
More than 140 bug fixes from the last beta to improve performance, stability, security and features.
This beta is available in more than 60 languages - get your local version.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6b3 [11-19-09]

What’s New in Firefox 3.6 Beta (revision 3) Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

(NEW) Changes to how we allow third party software to integrate with Firefox in order to prevent crashes.
(NEW) The ability to run scripts asynchronously to speed up page load times.
More than 80 bug fixes from the last beta to improve performance, stability, security and features.
This beta is available in more than 60 languages - get your local version.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6b2 [11-11-09]

What’s New in Firefox 3.6 Beta (revision 2) Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

More than 190 bug fixes from the last beta to improve performance, stability, security and features.
This beta is available in more than 45 languages - get your local version.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.6b1 [11-01-09]

What’s New in Firefox 3.6 Beta (revision 1) Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

This beta is available in more than 50 languages - get your local version.
Users can now change their browser's appearance with a single click, with built in support for Personas.
Firefox 3.6 will alert users about out of date plugins to keep them safe.
Open, native video can now be displayed full screen, and supports poster frames.
Support for the WOFF font format.
Improved JavaScript performance, overall browser responsiveness and startup time.
Support for new CSS, DOM and HTML5 web technologies.

Developers can find out about all the changes and new features at the Mozilla Developer Center.

v3.5rc3 [06-26-09]

What’s New in Firefox 3.5 (Release Candidate) Firefox 3.5 (Release Candidate) is based on the Gecko 1.9.1 rendering platform, which has been under development for the past year. Firefox 3.5 offers many changes over the previous version, supporting new web technologies, improving performance and ease of use, and adding new features for users: This release candidate is now available in more than 70 languages - get your local version. Improved tools for controlling your private data, including a Private Browsing Mode. Better performance and stability with the new TraceMonkey JavaScript engine. The ability to provide Location Aware Browsing using web standards for geolocation. Support for native JSON, and web worker threads. Improvements to the Gecko layout engine, including speculative parsing for faster content rendering. Support for new web technologies such as: HTML5

v3.5rc2 [06-21-09]

v3.5b4 [04-29-09]

What’s New in Firefox 3.5 Beta 4 Firefox 3.5 Beta 4 is based on the Gecko 1.9.1 rendering platform, which has been under development for the past 10 months. Firefox 3.5 offers many changes over the previous version, supporting new web technologies, improving performance and ease of use, and adding new features for users: This beta is now available in 70 languages - get your local version. Improved tools for controlling your private data, including a Private Browsing Mode. Better performance and stability with the new TraceMonkey JavaScript engine. The ability to provide Location Aware Browsing using web standards for geolocation. Support for native JSON, and web worker threads. Improvements to the Gecko layout engine, including speculative parsing for faster content rendering. Support for new web technologies such as: HTML5

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Predicted future versions and notices:

The doDownload.com constantly monitors the update of all programs, including information from the Firefox Beta 22.0 changelog file, however sometimes it can happen that data are not complete or are outdated.We assume that author continue's to develop 22.1 version with further advanced features, and soon you will be informed. Equally important 23.0 upgrades of the program we will continue to monitor. Full Firefox Beta description has been compared with the overall software database and our algorithm has found the following applications (are showed below).

(7.42MB, Extension: EXE)