The ESR release has been designed for companies, organizations and users who cannot keep up with deploying new Firefox versions every six weeks. Firefox ESR releases will follow the rapid release process, but increase only by a minor version whenever the standard version increases by a major version. Regular Firefox 10 users will be moved to Firefox 11 in six weeks time, while Firefox 10 ESR users will be moved to Firefox 10.1 instead.

The ESR release will be offered separately from the regular version of Firefox. Another important change in Firefox 10 is that add-ons are now automatically set to be compatible if they have also been compatible with Firefox 4. This ends the majority of the add-on compatibility issues that Firefox users experienced whenever a new major version of the browser was released.

The beta changelog lists the features one expects from a six week release cycle with the new hidden forward button the most notable change. Firefox 10 furthermore adds support for CSS3 3D-Transforms, anti-aliasing for WebGL, full screen APIs that can be used to build web apps that run full screen and support for the bdi element for bi-directional text isolation.

Developers can make use of the new CSS Style Inspector and IndexedDB APIs that match the specifications more closely

The previously announced silent update option has not made it into this version of Firefox. Mozilla aims to release the new feature with Firefox 13, which is expected to launch in the beginning of June.

Firefox users can expect to see update notifications later today. Please check out our Firefox 10 What’s New guide which looked at the changes in the Firefox 10 Aurora version.

Update: Firefox 10 Stable (here) is now available at the official Mozilla website.

Update 2: Firefox 10 ESR download links are now also available. Click here to go the page.

Firefox 11 Stable will be released in 3 months. Users running the version of the browser right now might be interested in the changes and new features that Mozilla has implemented into the browser.

Firefox 11 is all about web standards support. Firefox users not interested in web development won’t find new features or changes that impact their daily browsing habits. The feature coming nearest to this is support for SPDY, a transport protocol designed by Google to replace HTTP eventually. The protocol is currently only supported by a handful of web properties and applications. Google Chrome supports it, as do the majority of Google properties.

The protocol offers several benefits over standard HTTP. Connections will always run on SSL (no eavesdropping), servers should see reduced load and high latency users should see improved page loading times.

The preference is off by default. Users who want to enable the feature need to enter about:config into the Firefox address bar and filter for the term network.http.spdy.enabled in the preferences window. A double-click on the preference sets it to true which means that it is enabled.

A new battery API has been introduced in Firefox 11, which can provide web developers with information about the device’s battery status among other things.

Web developers do also benefit from new web development tools added to Firefox 11. This includes free-form style sheet editing and 3d views of web page structures.

More information about those tools are available here.

A list of all new features of Firefox 11 at the time of writing is available on Mozilla Hacks. Firefox users who have just been switched to Firefox 10 Beta or Firefox 9 Stable can use the posted links to find out what’s new in their version of the browser.

Update: Mozilla aims to integrate add-on syncing into Firefox 11 as well. (thanks Kshitij)

A new version of Firefox appeared on the official Mozilla ftp server today, only a day after the release of Firefox 9. News about the release of Firefox 9.0.1 are scarce at the moment.

The only indicator is a critical bug listing on Bugzilla that was likely the cause for the rushed new version. Bug 712490, Tracking bug for build and release of Firefox 9.0.1, does not reveal additional information about the nature of the bug. The only information to gather from the bug listing is that it affects all Firefox platforms and versions.

Bugzilla lists one additional bug with a normal severity rating which makes it very unlikely that it has been the cause for the rushed release. The bug is preventing custom app updates on Linux versions of the Firefox web browser.

Firefox 9.0.1 is currently being distributed to Mozilla ftp servers and the distribution network. It is likely that Firefox 8, Firefox 8.0.1 and Firefox 9.0 users will receive update notifications in the next 24 hours.

The Mozilla website is currently listing Firefox 9.0 as the latest web browser version on the Get Firefox download page. Release notes and bug fix pages for Firefox 9.0.1 have just been created. They are however currently displaying a copy of the Firefox 9.0 release notes and bug fixes.

It is likely that the information will get updated in the next hours. Firefox users who are experiencing issues in the browser may want to go ahead and download version 9.0.1 early to see if the new release resolves the issues.

Everyone else is probably better off waiting for the official release announcement which hopefully will provide additional information on the issue. (Thanks Midnight for the tip)

I have covered all Firefox 9 changes back when the Aurora version of the browser was released. Aurora versions on the other hand are not always what final users can expect from the browser.

The biggest new feature that Mozilla introduces in Firefox 9 is Type Inference which improves JavaScript performance significantly by using inferred type information. Mozilla noted that the new feature can speed up the browser’s JavaScript performance by up to 30%. Users will usually see less than that percentage though in their day activities.

The developers furthermore have added support for font-stretch, improved support for text-overflow and improved overall standards support for HTML5, MathML and CSS.

Mac OS X Lion users benefit from the new two finger swipe navigation and improved theme integration.

The release notes list several stability enhancements and bug fixes that have made their way into the browser (check the complete list of changes for details, linked on the release notes page).

Most Firefox users can probably wait the day until the browser is officially released by Mozilla. Users can then update Firefox with the browsers automatic update feature, or by downloading the new version from the official website.

Firefox users who experience issues with the current stable version, for instance crashes, may want to install the new version as soon as possible to resolve the issues.

Those users can download Firefox 9.0 Final from third party websites such as Softpedia. Please note that Softpedia only hosts the English version of the browser.

Have you tried Firefox 9 yet? If so, what’s your impression of the new version?

The Firefox release was pulled from the Mozilla server and things went quite for a few days. Today, Mozilla has released Firefox 8.0.1 to the public.

What does that mean for users who have downloaded the previous version that was pulled? These users need to download Firefox 8.0.1 for their computer manually from Mozilla again and install it over the current version.

Firefox 8.0.1 fixes two issues. First a Mac OS X crash that can occur when a Java applet is loaded in the browser with Java JRE 6.29 installed, and second a startup crash on Windows that is caused by versions older than 7.6.2 of the popular RoboForm extension.

Firefox users who are not on a Mac with that particular version of Java or on Windows with one of the affected RoboForm extensions do not need to update the browser right away. While it certainly does no harm, it won’t give them any benefit either (other than the reassurance that they are running the latest version of the browser).

Firefox users interested in the Firefox 8.0.1 release notes find them on this page. The internal updater should have picked up the new version by now. Users who already have version 8.0.1 installed should visit the download Firefox page to download the new release version manually for their language and operating system.

Update: Some users have reported that the new update is installed on systems where the pulled Firefox update has been installed. It appears that it may not be necessary to download the new version manually after all.

A fast release like this usually indicates a serious problem that needs to be addressed right away. Most issues that require an immediate response are security related in nature. This time though it seems to be a popular add-on that is causing stability issues for Firefox 8 users.

An extension block request has been posted at Bugzilla. The request to hard block the popular Roboform extension has been added on November 2. According to information posted there Firefox 8 users are experiencing the majority of crashes while users of other Firefox versions are also experiencing crashes but to a lesser extent.

Add-ons that are blocked can usually be added to a blocklist remotely. This did not work in the case of the Roboform add-on as it was hooking dlls into Firefox which needed to be blocked by adding code to the browser.

The changelog has not been posted yet, it will later be available on this page. It is not clear if additional patches have made it into Firefox 8.0.1.

For now, we can only assume that the Roboform patch is the only code change in the new version of the web browser. This means that Firefox users who do not work with Roboform do not need to update their version of the browser to the latest version right away.

The Mozilla homepage is currently listing Firefox 8 as the latest version. Third party websites like Softpedia are already hosting the new version on their servers.

I’ll update the news as soon as the update is available at Mozilla.

The official release notes do not paint a pretty picture, new features are scarce. This becomes obvious when you look at the first new feature listed on the release notes page: The forward button is now hidden by default and becomes available only after the user has navigated back. This new change is only available for Windows users currently.

Other changes include anti-aliasing for WebGL, new CSS Style Inspector which can be helpful for web developers, integration of the new full screen API to build full screen web applications and support for CSS3 3D-Transforms.

That’s not a lot and nothing to get to excited about. Sören Hentzschel discovered additional under the hood changes in the new browser version. The Customize option that allows Firefox users to drag and drop interface elements to another location is now highlighting screen elements that cannot be moved around.

Other changes include improvements in cursor key scrolling , a better Firefox Sync installation workflow and the ability to display statistics about HTML5 videos via right-click > Show Statistics.

The Firefox development team plans to integrate additional features into the release. Softpedia has published a list that includes a new tab page, better suggestions in the Firefox address bar, the ability to import settings and data from Google Chrome and silent updates which basically updates the web browser without user interaction, much like Google Chrome does.

Have you had the chance to play around with Firefox 10? If so, what is your impression of the web browser and your opinion on the new features introduced in the version?

Something was not working as expected, and so the search for a fix began. My first thought was that the Compatibility Reporter needed an updated, checked the official site and noticed that none was available there.

I then checked the add-on manager in the browser to see if I could re-enable the disabled add-ons. This too was unfortunately no possible.

Next step were the Firefox Options, I thought that Mozilla maybe had added a switch or flag to the options to prevent automatic add-on enabling. This too was not the case.

Last and final step was my decision to force compatibility directly in the about:config dialog, and this worked. But lets start at the very beginning. Enter about:config in the address bar and tap on the enter key. You see a big list of parameters. Enter compatibility at the top to filter for all parameters with compatibility in the name.

If you have the Add-on Compatibility Reporter installed you will see a large list of compatibility parameters. They start at Firefox 3.6 and go all the way up to Firefox 9. Yes, that is right. My take on this is that the parameters are added by the Compatibility Reporter, and that the program was configured to add compatibility up to Firefox 9. Considering that Aurora is now Firefox 10 and the Nightly builds Firefox 11, it is safe to assume that we will see an update of the program soon that remedies the situation. For now, you have to add the compatibility information manually. Right-click in the listing and select New > Boolean.

Enter extensions.checkCompatibility.10.0a as the name and select the value false on the next page. Restart the browser afterwards. If everything worked out correctly your add-ons should all be enabled again in the Firefox web browser.

I covered the major changes of Firefox 8 back in August when it was released to the Aurora channel which is a new release channel between the nightly releases and beta releases of the browser.

Probably the biggest new feature of Firefox 8 from a security perspective is how the web browser handles third party add-on installations. You may have encountered those while installing a security suite on your computer or other security related products. Before Firefox 8 no checks were performed when a third party software installed an add-on for the browser. Third party add-ons were installed and enabled right away and without user notification, which, from a security standpoint, left the browser wide open for local attacks.

Firefox 8 introduces other features as well. The browser gives users more control over add-ons after upgrading to a new Firefox version. Users can now disable or enable individual add-ons on first start with Firefox suggesting add-ons that may not work due to incompatibilities.

Firefox users can furthermore configure the browser to only load the selected tab on browser start, and the remaining ones once they are activated by the user. This can speed up the start significantly. The feature can be enabled under Tools > Options > General.

The browser ships with other minor improvements and changes. Included in the browser is now a Twitter search engine to search for Twitter messages from the browser’s address bar and search bar.

The browser is already available for all supported operating systems and languages on the official Mozilla FTP server. Only a handful of official mirror servers list the Firefox 8 Stable releases currently. This is certainly going to change in the next hours. Download portals like Softpedia or Major Geeks will surely have the Firefox 8 release available for download before it is distributed to all mirror servers and announced officially on the Mozilla website.

Firefox 7 users who are not in a hurry should wait until the release is officially announced by Mozilla. Their browser’s auto-updating feature will recognize the new feature and prompt for an upgrade to Firefox 8 automatically.

The beta release notes are available here. They will be converted into the final release notes once Firefox 8 has been officially announced by Mozilla.

Still, I decided to do some research and found out that I’m not the only user affected by the Update Failed message. I received the error message running Firefox Aurora, others running the latest stable version of the browser.

First thing I noticed was that the Firefox Aurora version that I was running was not automatically updated anymore. The version was a few days old and checking manually for updates returned the message that the browser was up to date (turned out later it was not).

When you look at the Firefox Help forum you get a lot of recommendations. This ranges from malware to plugins or extensions that affect the updating mechanism to files that previous updates left behind in the Firefox installation folder.

Solutions

If you have files in the defaults\pref folder in the Firefox installation folder (C:\Program Files\Mozilla Firefox\defaults\pref) folder other than the file channel-prefs.js then the updater didn’t remove those files or wasn’t able to do that because other software (possibly visualization software) had prevented that. That causes Firefox to override correct prefs with older prefs from firefox.all. [source]

Enter about:config in the Firefox address bar and filter for the term app.update.url there. Make sure the url begins with https://aus3.mozilla.org/.

Another possible cause that was mentioned quite often were third party extensions and plugins. Google Update was mentioned for instance several times in various Mozilla forum threads. I’m personally not really sure why the plugin gets installed into Firefox in the first place. I did notice that a Pando Media Booster plugin was installed on my system which I have not heard about before. I suspect that it was installed with the Might and Magic: Heroes VI game that I installed recently as it is commonly installed with games, especially MMOs.

Uninstalling the software from my system did not resolve the updating issue. It is not conclusive if the plugin had something to do with it though.

My solution was the following: I went to the Mozilla Firefox download page and re-downloaded the latest version of the web browser from there. I then installed it which did update my version of the browser to the latest version. It is to early to say if it fixed the issue completely, but I have not received the message ever since.

The company was quick enough to provide a temporary solution for the bug that brought back all the add-ons for affected users. We covered the issue and workaround here in detail.

Firefox 7.01, the update that fixed the hidden add-on issue is now available for all users. It can be downloaded from the official website or via the web browser’s internal updating. To do that one would have to click on Firefox > Help > About Firefox to trigger the check for a new version of the Internet browser (assuming that the one button Firefox menu is the preferred layout).

This new Firefox release fixes only this single issue. Some users have questioned why Mozilla did not catch the bug in the Nightly or Aurora phase of development. While it is probably to easy to link the bug to the rapid release cycle, one has to consider the fact that the accelerated release process could have something to do with it.

Taking into consideration that this is the first major bug, and that the last two releases did not contain serious bugs that required an emergency patch, it is to early to tell if the rapid release process had any influence here.

Tech interested users and websites like mine will however look closely at the coming releases to see if history repeats itself, so to speak. I give Mozilla the benefit of the doubt and assume that a bug like this could have been missed before the rapid release cycle as well.

Please let me know what you make of it.

Update: Mozilla Thunderbird, the email client, has also been updated to version 7.0.1.

Mozilla notes on a newly created support page over at the official website:

There is an issue with Firefox 7 that may have caused some or all of your add-ons to be hidden.

Mozilla furthermore notes that the company is working on an update that will fix the issue and restore all hidden add-ons so that they can be managed again in the browser.

An add-on has been released in the meantime that fixes the issue for affected systems. The Add-on Recovery Tool – Firefox 7 is available at the Mozilla add-on repository.

All affected users need to do is to click the Add to Firefox button on the add-on page to install the add-on. This triggers the usual prompt to install or cancel the add-on installation.

This triggers a Restart Firefox prompt. To restore the add-ons click the Restart button. You can alternatively click on Later to restart the browser at a later time. It is however suggested to restart right away to see if the add-on fixed the disappearing add-on issue.

It is very likely that Mozilla will post an update in the coming days to resolve the issue for all affected users and future users of the browser version.

Mozilla notes that users should not confuse the this bug with add-ons that have been disabled after updating the browser. Disabled add-ons should still be visible in the browser, while add-ons affected by the bug are not visible at all there.

Have you updated recently to Firefox 7? If so, did you experience the issue described here?

Update: The add-on has been pulled from the Mozilla add-on repository. It is no longer required as Mozilla has moved on to a new stable version of the browser.

The memory usage of the browser was usually in the 300 to 400 Megabyte range on my computer, with a reasonable amount of tabs open and extensions installed. Reasonable in this regard means ten or less.

After updating Firefox to version 7, that memory usage went down to around 200 Megabytes, with the same amount of extensions installed and tabs open.

That’s a significant improvement for a browser that is perceived as a memory hog by many. Firefox users with a reasonable amount of RAM installed on their computer might not notice a difference in performance, but users with limited amount of computer memory surely will.

Another observation here is that the garbage collection and releasing of memory has been optimized as well, so that Firefox users will notice a drop in RAM use every now and then.

Firefox stable users, who are currently running Firefox 5, will have to wait another three months or so before they can update their version of Firefox to version 7. Beta users, currently running beta 5 will get access to the new version in about six week’s time.

Conceivable Tech report that Firefox 7 ships with additional improvements and features, among them an optimized synchronization feature, better font rendering, and a new Azure 2D graphics API that improves the browser’s 2D graphics performance significantly.

Firefox 7 scores better in the HTML5test, with a score of 312+9 out of 450. That’s less than 20 points from Google Chrome 14 which scores 329+13.

Firefox 6, the next beta and stable version of the browser, in contrast will be a rather uneventful update.

Computer users interested in the latest Aurora build of the browser can download it from the official Mozilla website. Existing Firefox Aurora users can update the browser with a click on Help > About Aurora.

If you are already running or testing the latest Firefox 7, what’s your impression so far?

Firefox 4, or more precisely its only update Firefox 4.0.1 was released April 28, less than two months ago.

Firefox 5, which has been released yesterday is seen by Mozilla as a security update for Firefox 4. It in turn means three things:

• Mozilla Firefox 4 users will not get any more updates
• Firefox 4 users who have not updated yet are running a browser with security vulnerabilities
• Support for older versions of the browser has been reduced significantly

Some users might say that it is not all that bad. Just update from Firefox 4.0.1 to Firefox 5 and you are protected again, and update again from 5 to 6 and so on. Some arguments speak against this practice. Enterprise users need to do a lot more testing because of the new release process, and users who came to rely on specific add-ons, might have to disable them or force compatibility on them to get them to work in the next major version of the browser.

Mozilla notes that the major version updates are typically less likely to cause incompatibilities and other problems, due to the rapid release process which pushes out smaller releases regularly instead of big releases occasionally.

One thing that I’m personally a bit confused about is whether automatic updates are applied to Firefox 4, or not. I installed a test version, and while it shows a new update for the browser under Help > About Firefox, it does not seem to apply that update automatically when I close the browser and open it again. The Aurora release on the other hand applies updates automatically on every start.

Does that mean that Firefox 4.0.1 or 4.0 users are not getting Firefox 5 delivered as an automatic update? If that is the case, does it mean that Firefox 4 users are running a browser with known security vulnerabilities?

If you are running Firefox 4, I recommend to update to the latest version of the browser immediately.

What’s your take on all of this? Let me know in the comments. You can read the lifecycle policy discussion here at mozilla.dev.planning.

The beta release notes classify Firefox 4.0.1 as a security and stability release. Bugzilla lists a total of 53 bugs that have been fixed in the latest Firefox release. Of those, 12 have received a severity rating of critical, another 9 one of major.

The majority of critical issues have been crash and freeze related, only two address other issues. Other notable fixes include a issue where Adobe pdf documents with a size larger than 5 Megabytes could not be loaded in the browser, problems with the address bar and other text edits after loading pdf documents using Adobe Reader X and the inability to refine searches on Yahoo answers.

It can take up to 24 hours before the release is officially announced on the homepage and via the browser’s built-in updating functionality. It is likely that download portals such as Softpedia or Major Geeks will be faster and offer the download on their sites before the official announcement.

Since it is a security release it is important to update the web browser as soon as possible. A good starting point is the official Mozilla Release Mirrors listing which often provide access to downloads for all languages and operating systems before the final release announcement on the Mozilla Firefox website.

The release notes are accessible here.

New features are first introduced in nightly builds and then passed along to the other builds during development. Nightly builds on the other hand are usually the least stable builds, and stability in general is improved when builds are moved to a new update channel.

Firefox users, like Chrome users, should have the option to subscribe to any of the available update channels. This has been on paper only until now. Recent nightly builds now allow the user to switch to another update channel.

This is achieved with an about:config parameter that is currently not available by default. Users who make use of the parameter see the following selection menu when they click on Help > About Firefox.

Here they can switch between the Aurora, Beta and Release update channels. The new parameter works only in the most recent nightly builds of Firefox. It is however likely that the developers will make the switch easier in future versions of the browser.

For now, this is what has to be done. Enter about:config in the address bar of the Firefox web browser. Right-click the parameter listing and select New > String from the options. Enter app.update.desiredChannel and give the new parameter the value release, beta or aurora.

Restart the browser afterwards and open the Help > About Firefox menu. You will now see the option to update the channel. Just select the channel you want to switch to and click on Apply and Update to switch to that update channel. You can at anytime switch back to the previous channel or another of the available channels.

There does not seem to be an option to switch back to the nightly channel though.

Update: Mozilla has removed the option to switch between channels in Firefox. The only option to switch channels is to install the other version of Firefox on the system. You can also uninstall the current version of the web browser if you do not need it anymore.

While it may be tempting to upgrade to Firefox 4 right away, it is often better to test a new browser version before turning the temptation into action. The main reason for waiting is that some extension developers waited for the final Firefox release before starting work on making their extensions compatible with Firefox 4.

Firefox 3.6.16 and 3.5.18 are now available for all supported operating systems and languages. Existing users should receive update notifications during startup. The update check is also available manually from the Help > Check for Updates menu. It is alternatively possible to download the latest version from the Mozilla website directly. The download options are however deeply nested on the site, not as easy to find since Mozilla starting pushing the release of Firefox 4.

Both updates blacklist “a few invalid HTTPS certificates”. A post detailing the issue on the Mozilla Security blog points out that “users on a compromised network could be directed to sites using the fraudulent certificates [to] mistake them for [..] legitimate sites”. It would then be possible to deceive “them into revealing personal information such as usernames and passwords” or “into downloading malware”.

The issue is not Firefox specific, but Mozilla made the decision to protect Firefox users from possible exploits by blacklisting the revoked certificates.

Firefox 3 users should update their web browser as soon as possible, either to the latest Firefox 3 branch releases or the newly released Firefox 4, to protect the browser from possible exploits of the issue.

I have followed the development of the browser from pre-beta to the final release, and have to admit that it was not always a pleasant ride. It looked in the beginning as if the developers planned to make changes for the sake of changes, and not because they made sense or were demanded by the majority of the Firefox community.

Features like the new tab management module Panorama or the move to display mouse over link addresses in the address bar caused quite a stir among the community, and were disabled or changed in the end.

So what are the dominant new features that have been added to Firefox 4?

One can say that the new version improves the browser’s core considerably. The developers have made the Mozilla Firefox web browser faster, so that it does not take the rear ranks anymore in web browser benchmarks. The JavaScript performance alone has been improved by a factor of three (or more depending on the benchmark) when compared to the current stable Firefox 3 branch.

The version offers now comparable speeds to other fast browsers such as Internet Explorer 9, Opera or Google Chrome.

Firefox 4 comes with improved web standards support, including better CSS3, HTML5 and web graphics compatibility. Other notable features include hardware acceleration support, support for the HTML5 video WebM format, out of process plugins for Macs (Linux and Windows have it built-in since Firefox 3.6), privacy enhancements and multitouch support under Windows 7.

Interested users can access an overview, that compares the changes with previous Firefox browsers, on the Mozilla website.

As mentioned earlier, the Firefox interface has seen quite some changes. The dominating additions are the new Firefox button at the top of the browser that leads to most options of the menu bar. The menu bar has been removed as a result, and tabs have been moved above the Firefox address bar. Lastly, the status bar has been replaced and is now hidden by default.

Check out Firefox 4, How To Undo The Changes for instructions on how to revert the changes (get the old menubar back, move tabs below address bar, display status bar).

The add-on manager has been changed as well, it displays now in a tab instead of a standalone window. It is likely that some add-ons that have been working fine under Firefox 3 will not work under Firefox 4. You can try and force compatibility the following way:

Enter about:config in the Firefox address bar and hit the return key. Accept the warning message if this is your first time, and right-click on a blank spot afterwards. Select New > Boolean and enter the value extensions.checkCompatibility.4.0. Double-click the entry afterwards after clicking OK and change the value to false.

Firefox 4 Download

The final version has been pushed to the Mozilla ftp server where it is available for all supported operating systems and languages. It usually takes between 24 and 48 hours until the release is publicly announced on the Mozilla website. We do know however that Mozilla will announce the final release tomorrow, which is the time when downloads will become available on the web page.

The only option for now is to download the release from one of the official mirror sites (for instance this one) or from one of the big software portals. Softpedia for instance lists the download already on their download portal.

Outlook

The Firefox developers have already announced plans to ship a first patch shortly after the final release has been published on the website, as it is likely that the increase in users will reveal bugs that have not been discovered before. Plans overall are to release three new major releases in this year, which would mean a Firefox 7 release at the end of the year. Plans are plans on the other hand, and we have seen how delays can break them.

The release is currently available on the release server, and various mirrors throughout the world. Most mirror servers and the original Mozilla server block the download of the new release. One that does not is the server of the Umea University in Sweden. Just scroll down to Europe and click on that server to download the release candidate early.

The release notes page has not been uploaded yet. Users who have updated to or installed Firefox 4 will get a page not found error. It is likely that Mozilla will enable automatic updates and the release notes page in the next 24 hours.

Users of the beta of Firefox 4 may need to make a change to the Firefox configuration, if they have used it to override add-on compatibility. They need to write about:config in the address bar and hit the enter key on the keyboard.

The new setting to override add-on compatibility in Firefox 4 can be added with a right-click and the selection of New > Boolean from the context menu. The new value’s name is extensions.checkCompatibility.4.0 and it needs to be set to false.

Firefox 4 will not check an add-ons compatibility with the parameter set to false.

I will update the article when the downloads and the release notes page go life. (via)

Update: Mozilla has published the What’s New Page and the release notes. The release notes state the Firefox 4 contains “general stability, performance, and compatibility improvements”. The list of fixed issues contains several hundred entries and is accessible here. The release notes page lists the downloads for all Firefox 4 RC versions.

It is not clear yet why the new version has been pushed out , the release notes have not been posted yet and the new version ins only available via Mozilla’s ftp server and worldwide mirror servers.

Bugzilla lists a total of 23 bugs and issues that have been resolved in Firefox 3.6.15. One of the issues listed has received the highest severity rating blocker which could indicate that it is responsible for the update.

The release has fixed six critical issues as well which all but one seem to resolve crashes in the browser. The release does not appear to be security related, at least not on first glance over the issues that have been fixed according to Bugzilla.

It is likely that Mozilla will make an official release announcement later today. We will update this news post once the release notes have been published on the Mozilla Firefox website. The page they will be posted on is this one.