Firefox 136.0

What's new in this version:

New:
- You can now enable the updated Firefox sidebar in Settings > General > Browser Layout to quickly access multiple tools in one click, without leaving your main view. Sidebar tools include an AI chatbot of your choice, bookmarks, history, and tabs from devices you sync with your Mozilla account.
- Keep a lot of tabs open? Try our new vertical tabs layout to quickly scan your list of tabs. With vertical tabs, your open and pinned tabs appear in the sidebar instead of along the top of the browser. To turn on vertical tabs, right-click on the toolbar near the top of the browser and select Turn on Vertical Tabs. If you’ve enabled the updated sidebar, you can also go to Customize sidebar and check Vertical tabs. Early testers report feeling more organized after using vertical tabs for a few days.
- The Clear browsing data and cookies dialog now allows clearing saved form info separately from browsing history.
- Smartblock Embeds allows users to selectively unblock certain social media embeds that are blocked in ETP Strict and Private Browsing modes. Currently, support is limited to a few embed types, with more to be added in future updates.
- Firefox now upgrades page loads to HTTPS by default and gracefully falls back to HTTP if the secure connection fails. This behavior is known as HTTPS-First.
- On macOS, some background tabs will be moved to lower power cores, reducing energy usage
- Hardware-accelerated playback of HEVC video content is now supported on macOS
- Hardware video decoding is now enabled for AMD GPUs on Linux
- The Weather forecast on the New Tab page is expanding to additional regions, including Mexico, Brazil, Argentina, and Chile, as part of an ongoing regional rollout
- Address autofill enabled for users in the United Kingdom

Fixed:
- Firefox will now prefer the PNG format when copying images out of Firefox, allowing the preservation of transparency
- Various security fixes

Changed:
- For New Tab stories, the Save to Pocket action was moved from a button to the context menu along with other actions, such as Bookmark
- Due to recent changes in macOS Sequoia, the shortcut for completing search strings to .com addresses has been changed from Ctrl+Enter to Cmd+Enter

Enterprise:
Fixed:
- In some cases, Microsoft Entra SSO failed due to missing headers. This was fixed in bug 1945596.

Other Changes:
- HTTPS-First is now on by default. You can manage this behavior using the HttpsOnlyMode and HttpAllowlist policies.
- The new preference network.http.basic_http_auth.enabled allows you to completely disable Basic HTTP authentication

Policies:
- The ExtensionSettings policy has been updated to allow extensions to be enabled in private windows

Developer:
- The Developer Tools debugger editor now uses Codemirror 6, which improves performance

Web Platform:
- Added support for the Intl.DurationFormat object; this enables language-sensitive duration formatting
- Added support for the CSS :open pseudo-class for styling elements that can be toggled “open” to display more content
- Added support for the :has-slotted pseudo-class, allowing authors to style the contents of a <slot> element when it is not empty or not using the default value
- Added support for the CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers
- Added support for ARIA elements reflection
- Firefox now sends a referrer from meta refreshes and Refresh headers
- Added support for sending and receiving the AV1 video codec over WebRTC. Both singlecast and simulcast are supported for sending.
- Added support for sending multiple simultaneous versions of the same source over WebRTC, commonly called simulcast, with the H264 video codec. H264 is the second video codec after VP8 to be supported for sending simulcast.
- The value plaintext-only can now be specified for the contenteditable attribute, making the raw text of an element editable but without supporting rich text formatting
- Added support for the text replacement feature in an input field on macOS. Web content can enable/disable this using the HTML autocorrect attribute.