Furthermore, the folks on the 7 team have managed to cram a few last minute goodies into the OS, one of which we're particularly excited about. As you probably know from our in-depth preview of an early version of the software, we had a lot of issues with overflowing Facebook contacts in our phone. Microsoft has now solved that problem by enabling a contact filter system which looks for pre-existing matches to your Facebook contacts. If it doesn't find a match, it doesn't pull that contact into your address book (kind of like how Android filters Facebook friends). It's a welcome addition and should make the Facebook / Windows Phone 7 combo a lot more palatable to a lot of people. Furthermore, Microsoft has added functionality into the People Hub which will allow you to "like" someone's posts, and you'll be able to comment directly onto someone's Wall right in the hub. The company has also made tweaks and fixes focusing on feature discoverability (another issue we pointed out in the early look), along with the expected set of polishing and finish you'd expect from a product that's gone gold master.
Microsoft Windows Mobile 6.5
Microsoft Windows Phone 8.1