Following on from the release of Firefox 13 FINAL, Mozilla has updated its developmental branches to versions 14 (Beta), 15 (Aurora) and 16 (Nightly/UX) respectively. After the relatively exciting new features in version 13, what’s coming next? How does integrated social networking tools, panel-based download manager and improvements in OS X Lion users sound for starters?

Get a head’s up on what’s coming and discover which build is best for your personal needs with our updated guide to what the future holds in store for Firefox.

Firefox 13.0 FINAL
Without a doubt the recommended release for most users, as it’s the most stable build out there. As we revealed earlier in the week, version 13 introduces redesign home and New Tab pages, support for “tabs on demand” reloading of web pages when restoring the previous browsing session and a new Reset Firefox feature for quickly resolving common problems.

There's nothing visibly different to differentiate Firefox 14 from its immediate predecessor.

Firefox 14.0b6 Beta
The most notable new feature in version 14 is actually reserved for the mobile Android version, which will now support Flash video in Android 2.x and 4.x. Despite the promises of more radical changes when version 14 was in Aurora, the actual features making the transition to beta stage are relatively low key. The most notable is “Windows 8 Metro Firefox”, a project designed to build a Metro-specific version of Firefox for the next Windows release. This is still at the “definition” stage so no evidence of how it will look or perform currently exists. One other potentially game-changing feature is inline URL autocomplete, which has apparently landed in version 14. Seeing as this was backed out of versions 12 and 13 before they reached Final status, we’ll reserve judgement until we actually see it appear.

Firefox 15.0a2 Aurora
Firefox’s “alpha” build installs alongside either Firefox Final or Beta, allowing you to test it without affecting day-to-day browsing. Settings are shared between both builds, however, so install and use with caution.

The most interesting features in Aurora are still marked as “definition” or “development”, which means they’re not present and may not appear in Firefox 15 at all. These include integrating web apps into the desktop, which has already slipped back from version 14, the transition of the Firefox options dialogue to an integrated tab in Firefox itself (you can currently preview this in Firefox UX) and – the most intriguing of all – “Firefox Social Integration”.

This latter feature – still at “definition” stage – has four touch points: integration of persistent social notifications into the Firefox toolbar, a built-in share/recommend service in the Firefox toolbar, the integration of various news feeds, tickers, buddy lists and so on into a dedicated sidebar and the integration of chat, voice and other communication tools into a dock or floating window. None of these features are accessible in the current Aurora build.

Other changes are minor, and slipped from version 14, including Windows start-up performance improvements, incremental garbage collection and silent background updates. Mac users will also see improvements in its accessibility support.

Full-screen support is just one of the improvements slated in Firefox 16 for OS X Lion users.

Firefox 16.0a1 Nightly
Firefox’s Nightly channel gives users access to code hot off the press, and again it installs alongside other Firefox builds. It’s incredibly unstable, updated frequently and you’re just as likely to see new features disappear as appear.

Version 16 currently includes a number of improvements and new features, including support for OS X Lion’s newer features, such as full-screen mode and the new scroll bars. There’s opt-in activation for plug-ins for improved security, speedy session restore and the panel-based download manager. Developer Toolbar and Command Line tools for developers are also slated to appear, along with support for viewing PDF files in the browser window itself.

Some of these features can currently be previewed via Firefox 16.0a1 UX, the parallel nightly build of Firefox where interface improvements make their first appearance. We’d recommend all but developers and serious, knowledgeable enthusiasts avoid the Nightly builds of Firefox.

So, to summarise
Which version of Firefox should you try? There’s little available to preview in these releases to suggest anyone but developers and enthusiasts should install anything other than Firefox 13 FINAL.

If you do plan to take a look into the future of Firefox, back up if you plan before installing Beta or Aurora builds of Firefox. And If you do decide to give the Nightly or UX builds a try, consider using a non-critical machine or virtual setup (try VirtualBox) instead of your main computer, just in case…