Firefox 50 Released: Find out what is new

Mozilla Firefox 50.0 was released on November 15, 2016. Mozilla postponed the release of the new stable version of the Firefox web browser to ship it with noticeable startup improvements.

Note: if you are reading this article on November 15, 2016: Mozilla will release Firefox 50.0 today. It is already available on the FTP, but the roll out of the update may not have happened yet.

Mozilla Firefox 50 is the latest stable version of the browser. It replaces previous stable versions when installed, including the recently released Firefox 49.0.2, 49.0.1 and 49.0.

All beta channels have received updates as well. This means that Firefox Beta is now on version 51, Firefox Developer Edition on version 52, and Firefox Nightly on version 53. Firefox ESR, the Extended Support Release version of the browser was updated to version 45.5.

Executive Summary

1. Firefox 50 is the new stable version of Firefox. The release was delayed to integrate startup improvements in the browser.
2. Firefox 51 Beta, Firefox 52 Developer, and Firefox 53 Nightly are now also available.
3. Firefox ESR has been updated to version 45.5.
4. This is the last major release of Firefox in 2016.

Firefox 50 download and update

Installed copies of Firefox will pick up the new version once it is pushed out by Mozilla. Firefox ships with automatic updates enabled, which means that you don't need to do anything to upgrade Firefox if that is the case.

You may check for updates manually however to speed up the process. This is done by tapping on the Alt-key in the browser, and selecting Help > About Firefox. Firefox lists the current version in a window that opens, and runs an update check on top of that.

You may download all editions of Firefox using the links below instead.

• Firefox Stable download
• Firefox Beta download
• Firefox Developer download
• Nightly download
• Firefox ESR download
• Firefox unbranded builds information

Firefox 50 Changes

Faster Startup

The main reason why the Firefox 50 release got delayed: Mozilla identified issues in Firefox code in regards to how Firefox and its add-on SDK handle JavaScript loads. We have talked about this in detail back when the announcement was made, and I suggest you check out the article for details.

Only this much: Mozilla noticed better startup performance. Mileage varies and depends on the add-ons that are installed. A quick test by Mozilla revealed that startup performance improved by 35% on systems without add-ons installed, and more on systems with add-ons installed.

Find in page: limit to word matches

Firefox's Find in page functionality is handy as it enables you to search for content on a page quickly.

You can use the shortcut Ctrl-F to trigger the functionality. The new feature comes in form of a checkbox that you can enable for searches. When done, only full word matches are returned.

So, if you search for fire, all instances of the word on the page are highlighted while Firefox, firetruck or fireball are not.

Other Firefox 50 changes

• Playback video improved for sites without plugins with WebM EME support for Widevine on Windows and Mac.
• Download protection for a large number of executable file types.
• Firefox 50 highlights special permissions with a dot next to the i-icon in the address bar.
• Firefox highlights sites that use the camera with a new camera symbol in the tab bar.
• Tor browser security and privacy improvements integrated in Firefox.
• Firefox detects if Family Safety is active on Windows 8 or newer versions of Windows.
• The multi-process architecture rollout is still on going.
• Firefox 50 ships with a new system add-on called Application Update Service Helper
• Mixed content sites are shown with a green lock in the address bar instead of a green lock with an exclamation mark. A click on the icon highlights mixed content however.
• Firefox 50 ships with Lets Encrypt root certificate.
• New keyboard shortcut to load a page in Reader mode using Ctrl-Alt-R (on Mac Command-Alt-R). This works only on pages were Reader Mode is available for.
• Improved WebGL availability to more than 98% on Windows 7 and newer.
• New preference under General about:preferences#general to cycle through tabs in recently used order when using Ctrl-Tab. Not enabled by default.
• Added Guarani locale.
• Built-in set of Emoji added on systems without native support (Windows 8.0 and lower, and Linux).

Developer Changes

No major developer changes this time around:

• The Storage Inspector of the Developer Tools lets you delete individual items from IndexedDB object stores now.
• Memory Tool is enabled by default.
• Cookie prefixes _Host and _Secure are implemented.
• Referrer-Policy header has been implemented.
• Support for sandbox CSP directive has been added.
• Content Security Policy can be set for workers.
• Ping attribute of a elements abides by connect-src CSP 1.1 policy directive.
• Support for dragging and dropping multiple items via HTML5 added (DataTransfer.items).
• Set of File and Directory Entries API elements have been added to improve site compatibility.

Firefox for Android

• The user interface was simplified by combining the Recent Tabs and History page.
• Support for HLS videos via player overlay added.

Security updates / fixes

Security updates are published some time after the Firefox release. We will add those when they become available.

Additional information / sources

• Firefox 50 release notes
• Firefox 50 Android release notes
• Add-on compatibility for Firefox 50
• Firefox 50 for developers
• Site compatibility for Firefox 50
• Firefox Security Advisories
• Firefox Release Schedule