What's new in Firefox Quantum?

Released next week, Firefox 57 is the first to feature a major Servo component, Quantum CSS

Mozilla is rolling out the first version of Firefox to feature a major Quantum component on Tuesday November 14th, when v57 is released.

The organisation has been slowly revamping the old Gecko engine, which it inherited from Netscape, a process that one engineer described as "replacing a jet engine while the plane is still in flight." The new Quantum engine, which is written in Rust and C, promises to be faster and more stable.

Version 57 for the desktop, codenamed Firefox Quantum, will include the Quantum CSS rendering engine to convert HTML and CSS to pixels on screen. Quantum CSS has already been tested as part of Mozilla's experimental Servo browser. It is the first major component to make it into Firefox.

Other components from Servo will eventually find their way into Firefox too, including Flow, DOM and Render. Quantum CSS will be introduced for the Android browser in v58.

There are many aesthetic changes too. The first thing that users will notice is the new UI, its square tabs replacing the rather dated rounded ones of the current browser.

"Firefox Quantum feels right at home with today's mouse and touch-driven operating systems: Windows 10, macOS High Sierra, Android Oreo, and iOS 11," Mozilla says.

The old search widget will also vanish by default, with searches now conducted from the address bar with a dropdown listing a choice of search engines. The widget can be re-enabled in the settings, but this is not the case for the Classic Theme Restorer which will be consigned to history.

Mozilla promises significant improvements in the rendering speed, with claims that the ability to take advantage of multicore processors make it twice as fast as Firefox versions from this time last year and "often faster than Chrome, while consuming roughly 30 per cent less RAM". Having experimented with the pre-release 'nightly' version it certainly feels much snappier than the Firefox of yore.

A focus on privacy brings an option to turn on tracking protection, which blocks known tracking scripts, at all times, not just in private browsing mode. Protection against HTML5 canvas fingerprinting - another way that users can be tracked around the internet - will be released in v58, This is a feature borrowed from Tor Browser.

Less likely to be popular are changes to the add-ons system, with support for the previous XUL (XML User Interface Language) API being dropped. Mozilla is moving all add-ons to the WebExtensions standard that's used by all Chromium-based browsers and Microsoft Edge. While this means that extensions written for Chrome or Opera should run on Firefox, many existing add-ons will stop working until their developers have ported them to the new API. Add-ons that are compatible with version 57 are listed here.