A couple of weeks ago at Mobile World Congress Microsoft held a small press conference. During that event they talked about the next version of Windows Phone, but they were very careful to never actually say the name “Windows Phone 8.1.” Over the weekend Microsoft flipped the switch on a new OS in the “Works with” section for apps in the Windows Phone Store website.
This section in the Store is where you can see what version of Windows Phone the app will work with. If you visit the page for any app that is compatible with Windows Phone 8 you will now see “Windows Phone 8.1” also listed. This confirms a couple of things. 1) The update will indeed be called “Windows Phone 8.1,” and 2) all Windows Phone 8 apps will work with the updated OS.
That last feature is the really important part. Developers won’t have to do anything for their app to be available in 8.1. Microsoft did the same thing in the jump from 7.5 to 8. Developers will still have to do things to take advantage of new features in 8.1. One question will be how do 8.1 apps run on WP8? We will get more answers soon.