Mozilla has released Firefox 64 and it comes with new features such as the Contextual Feature Recommender, multi-tab selections, an improved Task Manager, and native Windows 10 sharing support. Mozilla has removed support for Live Bookmarks and RSS Feed subscriptions, including Atom and RSS feed subscriptions. The full release notes for Firefox 64 can be found here. This release also officially distrusts all Symantec certificates, which was originally slated for Firefox 63, but as too many users had not switched to a new certificate provider Mozilla delayed it to Firefox 64.
Source: https://www.bleepingcomputer.com/news/software/mozilla-firefox-640-released-heres-whats-new/