Microsoft today delivered a major update to its Facebook Beta for Windows Phone 8 and 8.1, providing a major UI overhaul and some great new features. And if you're using Windows Phone 8.1 already, this version of the app does integrate with the new social media extensibility capabilities in that platform.

This version of the app was previously promised by Microsoft's Joe Belfiore during a Reddit AMA chat.

"We've been working with [Facebook] on an update to [the Facebook] app too, targeted for the June timeframe," he wrote. "This update brings improvements to perf[ormance], having full-width photos in the newsfeed, and seeing photos and comments at the same time."

Here's what's new.

Updated design. This is the most obvious change. If you compare the new Beta app with today's normal Facebook app, you can see that the toolbars have been separated so that one is on the top and one is on the bottom (rather than having the two stacked up top). Oddly, it's still inconsistent with how the app looks on other platforms, in that what you see in each toolbar is reversed for some reason in the Windows Phone version.

Photos now full-width in the news feed. As promised. Before there were small borders on the sides.

See photos with comments together. Now, when you view the comments for a photo, you can still the see the photo.

Improved performance. Not much to say here. But the transitions between the main apps experiences—News feed, Requests, Message, Notifications and More—is indeed faster.

Video upload. When you do a status update or go to upload one or more photos, you can now include video(s) as well. Previously, you could only choose photos.

Support for additional languages. No details on which languages are supported, sorry.

Back in April, I revealed Microsoft's new Social Extensibility Framework in Windows Phone 8.1, which replaces the old OS integration for social networks in previous Windows Phone versions with an app-based integration model. In other words, when you choose to share something and choose Facebook (or Twitter, or LinkedIn, or whatever) from the Share menu, the appropriate app will now launch and you will perform the sharing from there.

I was curious to see whether the performance of this task had improved, since this has been a complaint point for upgraders. And while this is a bit unscientific, it does seem just a bit faster. Not that such a subtle change will halt the complaints.

Facebook Beta can run side-by-side with the normal Facebook app on your phone, so there's no reason to not at least check it out. You can download the Facebook Beta app for Windows Phone 8 and 8.1 from the Windows Phone Store.