The official release date of Firefox 53.0 is April 19th, 2017. Mozilla will release Firefox 53 on that day on its website, and through Firefox's automatic update system.

The new Firefox 53.0 release is important for a number of reasons. First, because it does not support a number of operating systems anymore. Second, because of the dropping of Firefox Aurora from the release cycle. You find details about these changes below.

Only Firefox Stable and Beta systems are updated on this release day. Firefox Stable is updated to 53, and Firefox Beta to 54. Aurora is not updated and removed soon, and Nightly is not updated to stay on version 55 to fill the gap that the removal of Aurora left. Firefox ESR 52.1 and 45.9 are also available.

Executive Summary

Windows XP, Windows Vista, 32-bit Mac OS X, and Linux support for processors older than Pentium 4 or AMD Opteron, are no longer supported.

Windows XP and Vista users on Firefox 52.x will receive security updates for another year, but no feature updates anymore.

Firefox Aurora is removed from the release cycle.

Firefox ships with two new compact themes (dark and light).

Compositor process enabled on qualifying Windows systems.

New legacy add-ons are no longer accepted on AMO.

Firefox 53.0 download and update

Firefox is configured to check for and download updates automatically. You can run manual checks for updates with a tap on the Alt-key on your keyboard, and the selection of Help > About Firefox from the menu bar.

The About Mozilla Firefox window checks for updates, and either downloads and installs any update it finds automatically, or on user request.

Direct download links for Firefox installation files:

Firefox 53.0 Changes

Firefox Aurora is out

We talked about the end of Firefox Aurora already here on Ghacks. Mozilla decided to remove the Aurora channel from the release cycle. The organization plans to migrate existing Aurora users to Beta eventually, and move features from Nightly to Beta directly in the future.

A special Developer Edition will be made available, based on Beta but with the same tweaks that the current Developer Edition ships with.

You can read more about the change by following the link above, or by visiting the FAQ page on the Mozilla website.

End of support for several operating systems

Firefox 53 won't support the following operating systems anymore:

Windows XP

Windows Vista

32-bit versions of Firefox on Mac OS X.

Processors older than Pentium 4 or AMD Opteron on Linux.

Mozilla plans to support the last working version for XP and Vista for some time going forward though. Users are migrated automatically to Firefox ESR, the Extended Support Release version of Firefox.

Mozilla plans to support XP and Vista versions of Firefox at least until September 2017. The organization plans to reveal the date supports end at the time, and will base it on the number of users who are still using XP or Vista.

More information is available on the Mozilla Support website, or our article on the subject.

Quantum Compositor on Windows

Mozilla Firefox 53.0 ships with a new GPU Process (Quantum Compositor) on supported Windows devices which reduces driver related crashes by 17%, Direct3D related crashes by 22%, and Direct3D accelerated video crashes by 11%.

Machines need to match the following requirements:

Windows 7 SP1 or up.

Multi-process enabled.

non-blacklisted graphics card.

That's about 25% of users according to Mozilla. To find out whether that is the case for your device, do the following:

Load about:support in the Firefox address bar. Check for the entries GPUProcessPid and GPIPRocess under Diagnostics.

Compact Dark and Compact Light themes

Firefox 53.0 ships with two new themes that resemble those found in the Developer Edition. Compact Dark and Compact Light are available under Appearance on the about:addons page.

Simply click on the enable button next to one of the themes to activate it. The themes do away with the curved tabs, and change a couple of other interface elements on top of that. Also, Firefox has an official dark theme now that it ships with.

Set default Referrer-Policy

Firefox users may set the default Referrer-Policy in Firefox by editing the network.http.referer.userControlPolicy preference. Basically, what the policy does is determine which referrer information should be included in the Referer header.

Type about:config in the browser's address bar and hit the Enter-key. Confirm that you will be careful if the warning prompt appears. Search for network.http.referer.userControlPolicy. Set the value to one of the following supported values: 0: no-referrer -- no referer information is included.

1: same-origin -- referer will only be sent for same-origin requests.

2: strict-origin-when-cross-origin -- full URL when a same-origin request is made, send origin for HTTPS to HTTPS requests, and no header to a less secure destinations.

3: no-referrer-when-downgrade (default) -- Referer is sent from HTTPS to HTTPS, but not from HTTPS to HTTP.

The default is used whenever sites don't specify a Referrer-Policy. (see Bug 1304623)

Permission notifications changes

The design of permission notifications that Firefox displays when websites request access to features such as the location has changed.

The dialog wont go away automatically anymore when you click somewhere on the page or switch tabs.

Other Firefox 53.0 changes

Developer Changes

Firefox 53.0 for Android

Out-of-process media decoding

Firefox 53.0 and newer versions of the Firefox browser for Android will handle media decoding out-of-process for improved performance on multi-core systems. (See Bug 1333323)

Right to Left language support (Arabic, Urdu, Hebrew and Persian).

Portrait mode supports two column tabs in the new version.

You may long-press on search suggestions to remove it from the browsing history.

Firefox 53.0.2

Firefox 53.0.2 was released on May 5th, 2017 to the stable channel. It features the following fixes and changes:

Form validation errors and date picker panel visibility changes (1341190) The non-standard showDialog argument to window.find is now ignored (1348409) Security fixes

Firefox 53.0.3

Firefox 53.0.3 was released on May 19th, 2017 to the stable channel. The new version of Firefox ships with two fixes and one change:

Fixed hangs when a proxy with NTLM authentication is used (1360574) Fixed "excessive resource usage" from the "captive portal detection service" (1359697) Bump preloaded security information expiration times (1364240)

Security updates / fixes

Security fixes are published after the release of Firefox 53. We will update the article once Mozilla publishes the update.

CVE-2017-5433: Use-after-free in SMIL animation functions

CVE-2017-5435: Use-after-free during transaction processing in the editor

CVE-2017-5436: Out-of-bounds write with malicious font in Graphite 2

CVE-2017-5461: Out-of-bounds write in Base64 encoding in NSS

CVE-2017-5459: Buffer overflow in WebGL

CVE-2017-5466: Origin confusion when reloading isolated data:text/html URL

CVE-2017-5434: Use-after-free during focus handling

CVE-2017-5432: Use-after-free in text input selection

CVE-2017-5460: Use-after-free in frame selection

CVE-2017-5438: Use-after-free in nsAutoPtr during XSLT processing

CVE-2017-5439: Use-after-free in nsTArray Length() during XSLT processing

CVE-2017-5440: Use-after-free in txExecutionState destructor during XSLT processing

CVE-2017-5441: Use-after-free with selection during scroll events

CVE-2017-5442: Use-after-free during style changes

CVE-2017-5464: Memory corruption with accessibility and DOM manipulation

CVE-2017-5443: Out-of-bounds write during BinHex decoding

CVE-2017-5444: Buffer overflow while parsing application/http-index-format content

CVE-2017-5446: Out-of-bounds read when HTTP/2 DATA frames are sent with incorrect data

CVE-2017-5447: Out-of-bounds read during glyph processing

CVE-2017-5465: Out-of-bounds read in ConvolvePixel

CVE-2017-5448: Out-of-bounds write in ClearKeyDecryptor

CVE-2017-5437: Vulnerabilities in Libevent library

CVE-2017-5454: Sandbox escape allowing file system read access through file picker

CVE-2017-5455: Sandbox escape through internal feed reader APIs

CVE-2017-5456: Sandbox escape allowing local file system access

CVE-2017-5469: Potential Buffer overflow in flex-generated code

CVE-2017-5445: Uninitialized values used while parsing application/http-index-format content

CVE-2017-5449: Crash during bidirectional unicode manipulation with animation

CVE-2017-5450: Addressbar spoofing using javascript: URI on Firefox for Android

CVE-2017-5451: Addressbar spoofing with onblur event

CVE-2017-5462: DRBG flaw in NSS

CVE-2017-5463: Addressbar spoofing through reader view on Firefox for Android

CVE-2017-5467: Memory corruption when drawing Skia content

CVE-2017-5452: Addressbar spoofing during scrolling with editable content on Firefox for Android

CVE-2017-5453: HTML injection into RSS Reader feed preview page through TITLE element

CVE-2017-5458: Drag and drop of javascript: URLs can allow for self-XSS

CVE-2017-5468: Incorrect ownership model for Private Browsing information

CVE-2017-5430: Memory safety bugs fixed in Firefox 53 and Firefox ESR 52.1

CVE-2017-5429: Memory safety bugs fixed in Firefox 53, Firefox ESR 45.9, and Firefox ESR 52.1

Additional information / sources

Now Read: The state of Mozilla Firefox

Summary Article Name Firefox 53.0 release: find out what is new Description Mozilla Firefox 53.0 Stable was released on April 19, 2017 to the public through the web browser's automatic update functionality, and on Mozilla's website. Author Martin Brinkmann Publisher Ghacks Technology News Logo

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