Now that Microsoft is finally ready to welcome Windows 8.1 into the world, it seems fitting for a major new app to join the fray. Yep, an official Facebook app has at last arrived for the Microsoft operating system, and it seems to have all the trimmings of what you would normally expect out of the eponymous social network. Indeed, it seems practically identical to the webpage, with status updates, news feeds, messaging and notifications in their familiar places. So far, the sole difference this has from other official Facebook apps appears to be the addition of a Windows Start tile. Don't go hurrying off to the Windows Store to get it just yet however, as it seems only those with the full RTM version of Windows 8.1 can get it for now -- everyone else will have to wait until 8.1 gets official later this morning.