The final version of Firefox 19 may have just left the den, but the Mozilla team are already hard at work on the beta version of Firefox 20, which just came out for Android today. Notable new features include a new per-tab private browsing feature that lets you alternate between normal and private tabs within the same session, customizable shortcuts for the home screen and support for additional ARMv6 devices. The browser also now supports lower-end phones with the minimum requirements of a 600MHz processor, 384MB memory and a QVGA display, which includes devices like the Samsung Galaxy Pop and the HTC Aria. Curious? Check out the release notes at the source, or if you're willing to tread those risky beta waters, just download it right now from Google Play.