The official version of Firefox 21 will be pushed soon after FTP is released.

It is reported that Firefox 21 will be officially available for external download on Tuesday, us time. However, users can download Firefox 21 on the Mozilla server. If you are an official Firefox 21 user, you are advised to pay attention to the update notifications pushed on Firefox.com at any time.

Up to now, Mozilla has not published official update logs for Firefox 21. However, we can find out from beta:

NEW: Enhanced three-state UI for Do Not Track (DNT ).

NEW: Firefox will suggest how to improve your application startup time if needed.

NEW: Preliminary implementation of Firefox Health Report (see FAQ ).

CHANGED: Ability to Restore removed thumbnails on New tab Page.

CHANGED: Add-ons History API removals in Places.

CHANGED: CSS-moz-user-select: none selection changed to improve compatibility with-webkit-user-select: none (bugs 816298 ).

CHANGED: Graphics related performance improvements (bugs 809821 ).

CHANGED: Removed E4X support from SpiderMonkey.

DEVELOPER: Implemented Remote Profiling.

DEVELOPER: Integrated, Add-on SDK loader and API libraries into Firefox.

HTML5: Added support for <main> element.

HTML5: Implemented scoped stylesheets.

FIXED: Some function keys may not work when pressed (833719 ).

FIXED: Browsing and Download history clearing needs unification to avoid confusion on clearing download history

In addition, although Mozilla has not released Firefox 21, the official Android version, it will still bring beta updates to users on Google Play.

The following is the Update log for this version:

NEW: Shipping Open Sans and Charis fonts for Web Content.

NEW: Ability to save media files on long tap.

CHANGED: Polished UI based on Holo theme.

CHANGED: CSS-moz-user-select: none selection changed to improve compatibility with-webkit-user-select: none (bugs 816298 ).

CHANGED: Graphics related performance improvements (bug 809821 ).

CHANGED: Removed E4X support from SpiderMonkey.

DEVELOPER: Implemented Remote Profiling.

DEVELOPER: Integrated, Add-on SDK loader and API libraries into Firefox.

DEVELOPER: DOM/content implementation for <input type = 'time'> Associated bugs.

HTML5: Added support for <main> element.

HTML5: Implemented scoped stylesheets.

FIXED: Download managers page is not updated after clearing private data (777639 ).

FIXED: In content UI cut off on small screens (840593 ).