You are viewing information archived from on 2014-02-12.

Mozilla Firefox 4 Beta 4 for Android and Maemo - Release Notes

Take your Firefox anywhere. Firefox 4 Beta for Android and Maemo is built on the same technology platform as Firefox 4 for desktop computers, just optimized for browsing on a mobile device. Check out the new and improved features, known issues, and frequently-asked questions. As always, you’re encouraged to provide suggestions to improve Firefox for mobile or file a bug in Bugzilla. If you need help, visit the Firefox Mobile Support Forum.

What's New in this Firefox 4 Beta

  • Add-ons
    • There are now over 100 add-ons for Firefox for Mobile, and counting.
  • Performance and Memory Usage
    • Startup speed has improved visibly. This was a top request from Beta 3 users.
    • JavaScript is much faster - almost 15% performance improvement in Beta 4 compared to Beta 3.
    • Memory and CPU usage is reduced, making the browser more responsive and stable.
  • Android
    • Fixed several keyboard issues (top feedback from Beta 3)
    • Improved support for tablets (like the Samsung Galaxy Tab) and small-screen devices (like the Motorola Droid Pro)
  • Firefox Sync
    • Improved user interface for easy connection with desktop Firefox
  • User Interface
    • Added an option to resize text to fit the screen when you double-tap to zoom in, to optimize the reading experience. This feature can be activated in the Firefox preferences. (This is also based on top feedback from Beta 3 users.)
    • Many miscellaneous bug fixes, usability improvements, and optimizations for a better experience
  • For developers

As well as these features from the previous Firefox 4 Betas:

  • Usability - support for Android hardware and software keyboards, Android-style menus, copy/paste in URL bar, search engines appear in the awesomescreen as you type, browse recommended add-ons through the add-on manager (read more)
  • File Handling - Support for uploading files, "Save as PDF" command in the site menu
  • Localization - fixed rendering of Arabic and Farsi text (on devices with Arabic/Farsi fonts installed)
  • Sync - New UI for simpler setup, support for custom Firefox Sync servers
  • Video - Full-screen open video and improved audio performance
  • Developers - localStorage API, orientation events
  • Sync - Shipping with the Firefox Sync feature built-in, Firefox 4 Beta synchronizes your Firefox history, bookmarks, open tabs, passwords and form data between your desktop and mobile.
  • Add-ons - Firefox 4 Beta offers add-ons; small pieces of software that let you change the look and feel of your Firefox to fit your browsing lifestyle.
  • Pinch-to-zoom (Android), double-tap, or use the volume rocker (Nokia N900) to zoom in and out
  • Open tabs as thumbnails let you easily see and open the site you want
  • Location-Aware Browsing gives you content and info relevant to your location
  • Save to PDF in the Site Menu lets you archive important docs like tickets and directions to view offline
  • Find in Page in the Site Menu lets you quickly find text on the webpage
  • Share Page in the Site Menu lets you send content to email, Facebook, Twitter and Google Reader
  • Forget Password in the Site Menu tells a website you no longer trust to forget your private data
  • Add Search Engine in the Site Menu lets you quickly add a new search engine to your Awesome Screen
  • Context Menu lets you Open in New Tab and Share by long tapping and holding a link
  • Smart Tapping lets you tap on links, widgets and other Web content with accuracy
  • Password Manager lets you choose to remember site password to avoid typing

For Developers

Firefox is an easy and open development platform to build fast, powerful and beautiful mobile web apps and add-ons. Use the latest web technologies like HTML5, CSS and JavaScript to innovate faster, more easily and extend your reach. You can build great sites and apps by tapping into the device capabilities of the phone, as well as create game changing add-ons. Visit the Mobile Developer Network to learn more about how you can build and showcase your innovations on millions of devices.

Build add-ons for mobile

Although Firefox for the desktop and mobile are built on the same technology platform, there are differences that will require developers to make changes to their add-ons in order to become compatible with Firefox 4 Beta for Android and Maemo. New: We now support restartless add-ons. Visit the Electrolysis and Add-ons wiki page and the Add-ons Training Week documentation to learn more.

What’s under the hood
  • The same browser engine as Firefox 4.0 beta for desktop
  • Fast JavaScript engine, using Mozilla’s “JaegerMonkey” just-in-time compiler
  • Leading Web compatibility
  • Optimized for ARM processors
  • Location-Aware Browsing
HTML5 and other web standards:

Known Issues

  • Users who have a large desktop profile using Firefox Sync may see some performance issues during the initial sync process. We are working to improve this in future releases.
  • Major changes to Firefox for mobile have been made which have resulted in multiple add-ons to break. Developers, please see the Electrolysis and Add-ons wiki and the Add-ons Training Week documentation to help you make your add-on compatible with Firefox.
  • Adobe Flash and other plugins are not supported. Currently, enabling the Flash plugin results in a compromised user experience across Firefox for mobile.

Known Bugs:

  • 617298 - There are some issues with SwiftKey that may cause it to crash or to prevent user from entering text in input fields.
  • 602252 - Loading some pages in Firefox causes long freezes on some Motorola phones, especially the Motorola Droid (or “Milestone”).
  • 606194 - Firefox fails to start on some Acer Liquid and Dell Streak devices.
  • 601222 - Firefox's JIT compiler is disabled on Samsung Galaxy S phones running Android 2.1 because of stability problems. JavaScript performance in Firefox 4 Beta will be slower on these phones than on other devices.
  • 535793 - Firefox for mobile will load an error page in place of the desired page while connecting to a network and loading a page at the same time
  • 624652 - Under some circumstances, Firefox for mobile may freeze on your Nexus S. Google is working on this issue, while we are also implementing fixes for the problem.
  • 626051 - Fennec crashes on certain nightly builds of Cyanogenmod 7 (an unofficial, community-developed version of Android).

System Requirements

Firefox 4 Beta is available for Android 2.0 and higher, and for the Nokia N900.

Firefox 4 Beta 4 requires around 14 MB of storage. Android 2.2 users can move Firefox to the SD card using Android’s Settings app.

This release requires a phone with an ARMv7 processor. Before installing Firefox 4 Beta on your Android phone, visit the Platforms and Device Requirements page. See a full list of supported and unsupported devices by visiting our System Requirements wiki.


Download Firefox 4 Beta by visiting on your Android phone, or Nokia N900. Visit the Platforms and Device Requirements page to make sure your phone meets the Android system requirements.

Developers: You can download a version of Firefox for mobile to your desktop in order to test, provide feedback, and build add-ons. Desktop builds are for development purposes only and don't have full functionality:

Frequently Asked Questions

Is Firefox 4 Beta available for my phone?
Firefox 4 Beta is available for Android (2.0 or higher) phones with compatible hardware, and for the Nokia N900. See the Android System Requirements to see if Firefox 4 Beta is compatible with your Android device. You can download the Firefox 4 Beta or download Firefox 1.1 for the Nokia N900 at If Firefox for mobile is not available for your device or platform, we're continuing to investigate ways to bring parts of the Firefox experience to you. Learn more about our mobile projects.
Is it called Fennec or Firefox?
Fennec is the codename of Mozilla’s mobile project, however, the official product name is Firefox. For pre-beta releases of Firefox, we call it by the project's name, Fennec.
How will Firefox keep me safe while I browse on my mobile?
Mozilla’s open source process leverages the experience of thousands of security experts around the globe, and Firefox includes features like instant Web site ID that checks on suspicious sites to ensure they’re what they claim to be. Customizable security settings to manage passwords, cookies, loading images and installing add-ons give you complete control over your browsing experience. Learn more.
How do I use the Firefox user interface to browse the Web?
To save space on your phone’s display, Firefox browser controls are stowed away to the sides of the screen. Swipe right to access your tabs on the left side of the screen. Swipe left to view one-touch bookmarking, back and forward, and access your browser tools. To let you see more of the Web site, your browser controls and Awesome Bar get stowed away out of view. when you scroll down a Web page, but they instantly reappear if you pan to either side. Tap on the on Web site ID to the left of the Awesome Bar to open the Site Menu to further manage your relationship with the Web page you are on.
What is the Awesome Screen?
The Awesome Screen pops up just by tapping on the location bar. It instantly brings up a smart list of your favourite history items and bookmarks and lets you easily select a search engine for your desired search. You can also customize your search engine list for maximum efficiency.
How do I zoom in and out?
For Android phones, pinch-to-zoom in and out or double tap. For the Nokia N900, you can use the volume button on the top of your phone, or double tap the screen with your finger to zoom in and out. Also, on the Nokia N900, Ctrl-up and Ctrl-down arrows will zoom in and out.
How do I bookmark a web page?
Go to the site you wish to bookmark. Touch the bookmark “star” button on the right side of your display.
How do I open a new tab?
Touch the new tab "plus" button on the left side of your display screen to open a new tab. Tabs appear as thumbnails so you can easily see which page you’d like to select.
What are Firefox Add-ons and how can I get them on my mobile device?
Add-ons are small pieces of software that let you add or change the look or functionality of Firefox. Install add-ons directly to your Firefox by swiping to the left and tapping on the browser tools "gear" button on the bottom right-hand side of your screen, then choosing the add-ons “puzzle piece” button to discover and install the add-ons that are most useful to you.
How can I share my Firefox bookmarks, history, tabs, and passwords between my desktop and my mobile?
Firefox Sync is a built-in feature of Firefox 4 Beta that lets you synchronize your desktop and mobile data. To use this feature, you must first install Firefox 4 Beta for the desktop. Then go to Tools, Set Up Sync and follow the prompts to create a Sync Account. Once you have an account on your desktop, go to Firefox on your mobile phone, tap on Browser Tools button. Scroll down the Preferences pane and tap Connect under the Sync section. A one-time code will appear. Go back to your Sync account info, select “Add Device” and enter the code from your phone. Learn more about setting up Firefox Sync on your mobile.
Do I need to setup Firefox Sync to use Firefox 4 Beta on my phone?
No. Although we think Firefox Sync is highly useful, it is feature that you can choose to use or not. The Awesome Screen will start to get to know you and take you to your favorite parts of the Web with minimal typing, even without Firefox Sync.
What are the trade-offs to using Firefox Sync in Firefox 4 Beta?
Although we think Firefox Sync is highly useful, it is still in its experimental phase. Those who use Firefox Sync and who have large desktop profiles, may detect performance issues on their mobile. We are working to resolve this in future releases.
What is Location-Aware Browsing? Is Firefox tracking where I am?
Location-Aware Browsing saves you time by allowing websites to ask you where you are. If you choose to share your location with a website, it can use that information to find nearby points of interest and return additional, useful data like maps of your area. It’s all optional – Firefox doesn’t share your location without your permission. Learn more about Location-Aware Browsing.

Developer Questions

Will a Firefox add-on I built for the PC work on mobile? If not, do I need to change it?
Although Firefox for the desktop and mobile are built on the same technology platform, there are differences that will require developers to make changes to their add-ons in order to be compatible with Firefox for mobile. Visit the Mobile Developer Network and Electrolysis and Add-ons wiki to learn more.
What browser engine does Firefox use?
The desktop and mobile versions of Firefox both use the Gecko rendering engine. The mobile version of Firefox uses Gecko version 4.0b8, which is the best performing browser engine Mozilla has ever released and includes exciting features such as radically improved JavaScript performance, geolocation support, worker threads, and much more.
What JavaScript engine does Firefox use?
Firefox includes the new “JaegerMonkey” JavaScript engine, an advanced JIT (“just in time”) compiler using tracing technology. The JaegerMonkey engine makes Web applications faster by compiling code as you execute it, allowing many types of CPU-intensive applications to run at near-native speed.
How do I develop a Location-Aware website for Firefox?
Firefox has implemented the first public draft of the Geolocation specification from the W3C. An overview on how to develop Location-Aware websites here.
Does Firefox on my mobile support HTML 5?
HTML 5 is the next major revision of HTML. The HTML 5 specification is ongoing, but there are several HTML 5 and related features that will enable Web developers to create more innovative websites and applications. Firefox includes important features like Location-Aware browsing, the <canvas> and <svg> tags, Web workers and offline storage.
Does Firefox on my phone support plugins?
There is no plugin support in Firefox 4 Beta for Android, and plugins are disable in Firefox 4 Beta for Nokia N900. On most Web pages that use the Adobe Flash plugin, the performance of the plugin on Nokia N900 didn't meet our standards, and the interactivity and performance of the entire Web page was negatively impacted. This was especially felt on pages with multiple instances of the plugin. Advanced users can enable plugins in Firefox for Nokia N900 for experimentation and testing only.
How can I get involved?
Help spread the word, test and improve Firefox 4 Beta and Go Mobile. If you’d like to learn more about ways you can get involved in other mobile-related initiatives, check out our Get Involved page. As always, your input is welcome.

View the Firefox 4 beta FAQ.