两天前Mozilla刚发布了Firefox 20的Android版，但Beta频道的21版本已经推出，新版本增加开源自定义字体Charis特性和HTML5兼容性优化。Mozilla用新的字体取代了Android的原生字体，带来了更佳的阅读体验，而HTML5兼容性的改进让HTML5test评分提高到了411(共500分)。 
以下是Firefox 21 beta for Android changelog: - 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 Manager page is not updated after clearing private data (777639).
- FIXED: In content UI cut off on small screens (840593).
可以从Google Play Store直接下载到Beta版本，正式版预计今年5月发布。 | 
