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

Fennec Alpha for Android and Nokia N900 Release Notes

Learn how we're bringing the Firefox experience to mobile devices, making Firefox the most customizable mobile Web browser in the world. Check out the new and improved features, known issues and frequently asked questions in this alpha release of Fennec for Android and Nokia N900. As always, you’re encouraged to give feedback or file a bug in Bugzilla.

What's new in Fennec Alpha for Android and Nokia N900

Fennec is the codename of Mozilla’s mobile project, however, the official product name is Firefox. For pre-beta releases of Firefox, we refer to it by the project's name, Fennec. This is an alpha release of Fennec.

Built on the same technology platform as Firefox 4 for desktop computers, Fennec is designed and optimized for browsing on a mobile device, yet ships with many of your favorite Firefox desktop features like Firefox Sync, Add-ons and the Awesome Bar. This alpha release brings Fennec to the Android platform, the fastest growing smartphone platform in the world.

The foundation of this release is based on enhanced responsiveness and increased stability, in conjunction with new and improved features that focus on customizing the browser to fit the individual exactly:

Get Up and Go

Shipping with the Firefox Sync feature built-in, Fennec synchronizes your Firefox history, bookmarks, open tabs, passwords and form data between your desktop and mobile. Just login with your Firefox Sync account info and Fennec gets to know you right away, taking you to your favorite parts of the Web with barely any typing. Don't worry about switching to a new phone, or having to type long URLs or passwords again. You can even leave your desktop in a moment’s notice and pick up right where you left off on your mobile phone.


Fennec is the world's first mobile Web browser to support add-ons; pieces of software that let you change or add features, functionality and the look of your Fennec to fit your browsing lifestyle. You can search for and install add-ons directly to your Android phone or Nokia N900 from the Add-ons Manager located in your browser tools.

Personalized Start Page

The Start Page gives you a snapshot of your online life while you’ve been away. Pick up where you left off with instant access to your Firefox desktop data, the tabs you had open last time you were browsing on your phone, and get suggestions for useful add-ons. Comign soon: See alerts of recent activity from your email accounts and your favorite social media sites!

Awesome Screen

The Awesome Screen pops up just by tapping on the Awesome Bar (location bar). It gets to know you and 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.

Touch Friendly UI

Swipe to the left or right of your screen to access your tabs, browser controls and tools, which are stowed out of the way while you browse the Web. Typing on a phone is hard, that's why you can bookmark a site with one tap, view tabs as thumbnails to easily see and open the page you want, and use the Awesome Screen to get to where you want to go in just a few a keystrokes.


Responsiveness is one of the major focuses for this release. We've redesigned Gecko to allow us to run the UI in a separate process from the web content which enables us to react much faster to user actions like scrolling and zooming.

More personalized than ever before, Fennec is packed with your favorite features and great improvements. Other highlights include:

  • Pinch-to-zoom (Android), double-tap, or use the volume rocker (Nokia N900) to zoom in and out
  • Tabbed browsing in thumbnail view lets 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 capture important content, like driving directions or a boarding pass, 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

These improvements build upon the features and additions in the last major Firefox for mobile release.

For Developers

Firefox is an easy and open development platform to build fast, powerful and beautiful mobile 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 for the first mobile Web browser to support them.

Build add-ons for mobile

Although Firefox for the desktop and mobile are built on the same platform, there are differences that will require developers to make changes to their add-ons. These changes are usually straightforward, visit the Develop for Mobile and Electrolysis and Add-ons pages 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 “TraceMonkey” just-in-time compiler
  • Leading Web compatibility
  • Engine optimized for ARM processors
  • Location-Aware Browsing
HTML5 Technologies:
  • Web workers
  • Offline storage
  • <canvas>
  • <svg>
  • Native JSON

Known Issues

  • Improvements to graphics performance in areas like scrolling, zooming, animations, and video will be coming to Fennec in our beta release
  • Major changes to Fennec have been made which have resulted in multiple add-ons to break. Developers, please see the Electrolysis and Add-ons wiki as a guide to help you make your add-on compatible with Fennec
  • Fennec, although compatible with Android 2.0 and above devices, has been optimized for the Nexus One. Your experience may differ on other Android devices. For more info, see the Android system requirements.
  • Known Bugs:
    • 584173 - The Awesome bar may flicker when you pan down the page
    • 575556 - File uploads do not work
    • 586288 - Iframes and scrollable divs are not scrollable
    • 536289 - FTP sites are not accessible

System Requirements

Fennec is available for download on the Android platform and on the Nokia N900 and N810 mobile devices.

Before installing Fennec on your Android phone, make sure your phone meets the Android system requirements.


Users on a Fennec nightly build will need to uninstall their build in order to properly install the Fennec alpha. The same procedure needs to be performed for users who want to go back to Fennec nightly builds from Fennec alpha.

Download Fennec by visiting on your Android device or Nokia N900.

Developers: You can download a version of Fennec alpha 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 Fennec available for my phone?
Fennec is available for Android (2.0 and above) phones, and for the Nokia N900. See the Android System Requirements to see if Fennec is compatible with you Android device. You can download the Fennec here or, you can download Firefox 1.1 for the Nokia N900 here. 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. Same as the desktop. 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 pieces of software that add functionality and let you customize Firefox exactly the way you like. Swipe to the left and select the browser tools “gear” button on the bottom right-hand side of your screen, then choose the add-ons “puzzle piece” button and search for and install the add-ons that are most useful to you directly from your phone.
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 Fennec that lets you synchronize your desktop and mobile data. To use this feature, you must first install the Firefox Sync add-on on your desktop and create a Firefox Sync account. Then go to Firefox on your mobile phone, tap on the browser tools, Add-ons Manager and select Firefox Sync. Tap "Connect," and enter your Firefox Sync login info to begin synchronizing. To learn more about setting up Firefox Sync on your mobile, watch this video.
Do I need to setup Firefox Sync to use Fennec 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. If you do wish to start using Firefox Sync on your mobile phone, remember you must first install the Firefox Sync add-on to your desktop and create an account.
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 platform, there are small differences that will require developers to make changes to their add-ons. These changes are usually straightforward, visit the Develop for Mobile and Electrolysis and Add-ons pages 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 1.9.3, 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 “TraceMonkey” JavaScript engine, an advanced JIT (“just in time”) compiler using tracing technology. The TraceMonkey 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 Fennec for Android and Nokia N900. On most Web pages that use the Adobe Flash plugin, the performance of the plugin 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 for experimentation and testing purposes only. We are working on ways for the user to have control of which sites to enable plugins for, as some sites, like YouTube, do work quite well.
How can I get involved?
Check out our Develop for Mobile page to learn more about how you can contribute to Mozilla’s mobile project. If you’d like to learn more about you can get involved in other mobile-related initiatives, check out our Get Involved page. As always, your input is welcome. Please provide your feedback using Firefox for mobile.

View the complete Mobile FAQ.