- 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.
- Enabled multi-process Firefox for Windows users with touch screens
- 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.
- Enhanced Sync to allow users to send and open tabs from one device to another.
- 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
- 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
- Redesigned Responsive Design Mode to include device selection, network throttling, and more