Firefox Release Notes

Added support for WebAssembly, an emerging standard that brings near-native performance to Web-based games, apps, and software libraries without the use of plugins.

Added automatic captive portal detection, for easier access to Wi-Fi hotspots. When accessing the Internet via a captive portal, Firefox will alert users and open the portal login page in a new tab.

Enhanced Sync to allow users to send and open tabs from one device to another.

Added user warnings for non-secure HTTP pages with logins. Firefox now displays a “This connection is not secure” message when users click into the username and password fields on pages that don’t use HTTPS.

Implemented the Strict Secure Cookies specification which forbids insecure HTTP sites from setting cookies with the "secure" attribute. In some cases, this will prevent an insecure site from setting a cookie with the same name as an existing "secure" cookie from the same base domain.

Various security fixes

Improved text input for third-party keyboard layouts on Windows. This will address some keyboard layouts that

• have chained dead keys
• input two or more characters with a non-printable key or a dead key sequence
• input a character even when a dead key sequence failed to compose a character

Removed support for Netscape Plugin API (NPAPI) plugins other than Flash. Silverlight, Java, Acrobat and the like are no longer supported.

Removed Battery Status API to reduce fingerprinting of users by trackers

Improved experience for downloads:

• Notification in the toolbar when a download fails
• Quick access to five most recent downloads rather than three
• Larger buttons for canceling and restarting downloads

Display (but allow users to override) an “Untrusted Connection” error when encountering SHA-1 certificates that chain up to a root certificate included in Mozilla’s CA Certificate Program. (Note: Firefox continues to permit SHA-1 certificates that chain to manually imported root certificates.) Read more about the Mozilla Security Team’s plans to deprecate SHA-1

Migrated Firefox users on Windows XP and Windows Vista operating systems to the extended support release (ESR) version of Firefox.

When not using Direct2D on Windows, Skia is used for content rendering

On Linux, Firefox now requires PulseAudio to play sound and no longer plays sound directly with ALSA.

Redesigned Responsive Design Mode to include device selection, network throttling, and more

Improved security for screen sharing, which now shows a preview and no longer requires a whitelisted domain

Enabled CSS Grid Layout, opening up a world of new possibilities for graphic design

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