Here is what is new and changed in Firefox 86.0

Mozilla released Firefox 86.0 Stable and Firefox 78.8 ESR to the public on February 23, 2021. The new versions of the browser are already available as direct downloads from the Mozilla website and as in-browser updates.

All development versions of Firefox are updated as well around the same time. Firefox Beta and Firefox Developer are moved to version 87, Firefox Nightly to version 88, and Firefox Android to 86.0 as it follows the stable channel's versioning.

You can check out the Firefox 85.0 release overview in case you want to take a look at it.

Executive Summary

Firefox 86.0 introduces a new privacy feature called Total Cookie Protection.
Firefox 85 and Firefox 78.7 fix security issues. The highest severity rating is high (second-highest after critical).

Firefox 86.0 download and update

firefox 86.0 stable

Firefox 86.0 is available by the time this article is published. Firefox users may select Menu > Help > About Firefox to check the installed version and run a manual check for updates. Unless deactivated, updates will be pushed automatically to Firefox installations.

Manual downloads are also available. The following pages list direct downloads for supported Firefox channels.

New features and improvements

Multiple picture-in-picture windows

firefox multiple picture-in-picture videos

Firefox users may open multiple picture-in-picture windows in the new release instead of just one. Each stream needs to be opened in its own tab in the browser, and the actual picture-in-picture windows may be moved around to view them all at once.

While it is not a mass-market appeal feature, it is useful for certain scenarios, such as following multiple matches on match day, or watching an event unfold through different camera perspectives.

You can check out our full review of Firefox's multi picture-in-picture feature here.

Total Cookie Protection

firefox total cookie protection

Total Cookie Protection is a new privacy feature designed to separate cookie data by website. Each site gets its own cookie storage and that means that access is restricted and not shared across all Internet sites.

Mozilla notes that it decided to make exceptions for non-tracking cookies that are cross-site that are needed, e.g. for sign-in purposes on sites. The organization notes:

Only when Total Cookie Protection detects that you intend to use a provider, will it give that provider permission to use a cross-site cookie specifically for the site you’re currently visiting

The new feature is enabled automatically when you enable the strict mode of Firefox's Enhanced Tracking Protection feature. Firefox users who want to try the new option may point their browser to about:preferences#privacy to set the Enhanced Tracking Protection preference to Strict on the page.

Mozilla introduced network partioning in Firefox 85, another privacy feature.

Other changes

Print functionality offers better integration with the operating system's printer settings and a "cleaner design.
Canadian Firefox users may now use credit card management and auto-fill automatically, as it is enabled by default. Users who don't want that can turn it off under Menu > Options > Privacy & Security > Autofill credit cards.
Performance and stability improvements by using the GPU process for canvas drawing and WebGL drawing.
Reader Mode works on local HTML pages.
Various Screen Reader improvements and improved link color contrast in Reader View.
Improved security by consolidating all video decoding in the new RDD process.
Linux and Android users are protected against stack clash attacks thanks to implemented mitigations.

Firefox for Android

Coming later.

Developer Changes

DTLS 1.0 is no longer supported for for establishing WebRTC's PeerConnections. The new minimum version is DTLS 1.2.
Improvements to the Tabs permission for extension developers (tab URL, title and favicon no longer require the tabs permission for host permissions for tabs.
New experimental base content security policy landed behind a flag that disallows remove code execution in extensions.
extensions.webextensions.tabhide.enabled has been removed because the tabs hiding API is enabled by default.
Windows.name is reset to an empty string if a tab loads a page from a different domain to prevent the new tab from accessing information that previous tabs might have stored.
Basic AVIF support is enabled. Some features, animated images and colorspace support, are still in development.
Developer Tools Toolbox shows the number of errors on a page.

Known Issues