隨著Mozilla FireFox 55的到來，這款開源瀏覽器走入了一個全新的階段，多線程的完善和正式引入讓它的性能終于開始趕上，不過老舊的插件（如Flash）讓瀏覽器在多線程運行時問題百出，在Firefox 55及以后的版本中，Mozilla將重點開始解決這些問題：比如，在55版本中，運行Flash控件將默認需要用戶確認，并且不再允許從本地調用此類內容等。同時從55版本開始，Firefox將開始支持WebVR。

　　還有一個顯而易見的更新是，搜索框和地址欄的關系變得更為緊密，您可以隨時在地址欄中設定所輸入關鍵詞的搜索引擎并立即開始搜索，由此可見在不久的將來，獨立的地址欄很有可能會被取消掉，搜索就像Chrome一樣容易。

　　與此同時，“同步”特性也有了較大的增強，同步菜單中引入了一個進入Firefox同步中心的入口，在這里可以管理多個設備的Firefox同步。

　　New

　　Browsing sessions with a high number of tabs are now restored in an instant

　　Sidebar (bookmarks, history, synced tabs) can now be moved to the right edge of the window

　　Fine-tune your browser performance from the Preferences/Options page.

　　Makescreenshotsof webpages, and save them locally or upload them to the cloud. This feature will undergo A/B testing and will not be visible for some users.

　　Added Belarusian (be) locale

　　Assign custom shortcuts to Firefox menu items on OS X and macOS via System Preferences > Keyboard > Shortcuts

　　Simplify print jobs from within print preview

　　Use virtual reality devices with the web with theintroduction of WebVR

　　Search suggestions are now enabled by default for users who haven't explicitly opted-out

　　Search with any installed search engine directly from the location bar

　　Changed

　　Breaking profile changes - do not downgrade Firefox and use a profile that has been opened with Firefox 55+.

　　Windows stub installer is now streamlined for simpler installation. Users requiring advanced install options should usefull installers.

　　The Flash plugin is now click-to-activate by default and only allowed on http:// and https:// URL schemes. This change will be rolled out progressively and so will not be visible to all users immediately. For more information see theFirefox plugin roadmap

　　Modernized application update UI to be less intrusive and more aligned with the rest of the browser. Only users who have not restarted their browser 8 days after downloading an update or users who opted out of automatic updates will see this change.

　　Developer

　　Insecure sites can no longer access the Geolocation APIs to get access to your physical location

　　下載地址：https://ftp.mozilla.org/pub/firefox/releases/55.0/