Level 78
Top poster
Content Creator
Malware Hunter
Aug 17, 2014
Firefox 90.0 is the latest stable version of the Firefox web browser. It will be released later today and most Firefox installations will pick up the update automatically.

Executive Summary​

  • Firefox 90 includes security fixes.
  • Firefox 78 ESR is the last version of Firefox that supports Flash.
  • FTP support is no longer available.
  • On Windows, updates are applied automatically in the background even when Firefox is not running.
  • New about:third-party page that highlights compatibility issues with third-party apps.
  • SmartBlock improvements.
Background updates on Windows

Firefox on Windows may download and install updates in the background on Windows starting with version 90, even if Firefox is not running. It is designed to improve the overall updating process. Chromium browsers use similar techniques when it comes to updating.

The new feature applies to stable versions of Firefox only, not to Firefox ESR.

A policy is available to block the new updating behavior. Windows administrators may disable the task in the Task Scheduler as well to block these updates.

Check out Mozilla is working on Firefox background updates on Windows for additional information on the task and policy.
Third-party injections on Windows

Firefox's new about:third-parties page lists all third-party modules that are not signed by Mozilla or Microsoft.

These may cause compatibility issues, e.g. crashes or other undesirable behavior.

Firefox displays the following information for each module:
  • Filename.
  • File version.
  • Vendor information.
  • Occurences.
  • Average blocking time.
  • Process ID.
  • Load duration.
  • Status.
An option to open the file location in the system's file browser is also provided.

firefox third-party modules
HTTPS-Only mode exceptions management in Settings

HTTPS-Only mode is a useful feature in Firefox that allows HTTPS connections only be default. Firefox attempts to upgrade HTTP to HTTPS connections automatically, similarly to how extensions such as HTTPS Everywhere work. If that fails, Firefox will display a prompt to the user.

The mode can be bypassed then to access the HTTP version of a site.

To manage exceptions, sites that are allowed to be loaded using HTTP, go to about: preferences#privacy, scroll down on the page and activate the new "Manage Exceptions" button.

https-only mode exceptions
Other changes
  • FTP support has been removed. The attempt to load FTP links or type ftp links directly in the address bar displays a prompt to pick a handler for the protocol in Firefox 90.
  • Print to PDF creates working hyperlinks in Firefox 90. Users who open the PDF documents can activate the links to open the linked resource.
  • SmartBlock version 2.0 improves privacy by blocking Facebook scripts by default but loading them when they are needed, e.g. when a user selects to sign-in to Facebook.
  • Open Image in New Tab loads the media in a background tab now.
  • Most Firefox installations without hardware accelerated WebRender will now use software WebRender.
  • Improved software WebRender performance.
  • Enterprise: AutoLaunchProtocolsFromOrigins policy is now available. Defines a list of external protocols that can be used from listed origins without prompting the user.
  • Enterprise: BackgroundAppUpdate policy controls the background updates feature on Windows.


Level 78
Top poster
Content Creator
Malware Hunter
Aug 17, 2014
Does anybody know if the proton appareance can still be deactivated via about:config in Firefox 90? and if the "compact" density in toolbar preferences still can be used? thanks.

Confirmed here on my Firefox 90, looks like it's still possible to disable "proton" and to enable "compact". please check screenshots below...



Level 37
Top poster
Nov 10, 2017
Firefox 90 introduces the next version of SmartBlock, the browser’s tracker blocking mechanism built into its private browsing and strict modes, which now has improvements designed to prevent buttons that let you log into websites using your Facebook account from breaking, Mozilla announced on Tuesday.

SmartBlock was first introduced with Firefox 87 in March, and if you aren’t familiar, here’s Mozilla’s description of how it works, from the company’s blog:
SmartBlock intelligently fixes up web pages that are broken by our tracking protections, without compromising user privacy.

SmartBlock does this by providing local stand-ins for blocked third-party tracking scripts. These stand-in scripts behave just enough like the original ones to make sure that the website works properly. They allow broken sites relying on the original scripts to load with their functionality intact.

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