We took a look at several apps in the Store, and they are all listed the same. The change apparently happened en masse overnight. That development bodes well for those that are waiting impatiently for the official announcement and demonstration of Windows Phone 8.1 because it means there should not be any compatibility issues for apps running on the updated OS.
For those that are still catching up, you can see our comprehensive summary of everything we know about the Windows Phone 8.1 update. A lot of information leaked before the SDK was sent out, but once Microsoft sent out “confidential” invitations to developers to evaluate the Window Phone update, the floodgates basically opened.
We are just a little over two weeks away from the Microsoft //Build/ developer conference where it is expected that all will be revealed.
sources: WindowsPhoneApps.es via WMPoweruser