Facebook yesterday updated its iPhone app to version 3.4, bringing enhancements to the News Feed and notifications UI as well as the option to check-in to Facebook Events on the go. For unfriending that cannot wait until you get back to your desktop, the app adds that, too.

The signature feature of the update, of course, is the mobile check-ins for Facebook Events. We previously reported that Facebook added another layer to its location-based functionality by including a check-in icon available on the day of a given event. The company had pledged to launch the feature soon on the iPhone and their mobile site. Yesterday's update fulfills that pledge.

Formerly, the only way you could check in to a Facebook Event was through Facebook Places, which entailed checking in to locations as you would with Foursquare or Gowalla. Now users can check-in to events themselves, opening up new possibilities for companies and individuals. For example, you could arrange contests at events.

To check-in to an event you have to have been invited and to have RSVP'd. If you're at the right place at the right time—the app uses your phone's time and location for this—you'll see a "Check In" button on the event page. You can also see who else is at the even through the "Here Now" section of the page or take a look at check-ins, comments, and photos through the "Recent Activity" area.

iPhone users can download Facebook for iPhone 3.4 from the App Store today. Android users will have to have check-in and unfriend the old-fashioned way for now.

This article, written by William Fenton, originally appeared on PCMag.com and is republished on Gear Live with the permission of Ziff Davis, Inc.