There have been lots of rumours that Microsoft are planning to discontinue the Microsoft Band, which would be shame as despite its limited feature set and dubious build quality is actually a nice device and something I still wear alongside my Moto 360. Anyway Microsoft have renamed the Microsoft Health app to Microsoft Band on Windows and Android (iOS will probably follow). I suspect the reason is that Microsoft’s original plan for the app was for 3rd party devices would use the app to sync health data to the cloud and the Microsoft Band was just one of the devices. It looks like plans have changed and now the app is just dedicated to the Band.
The app also updates the firmware of the Microsoft Band but there doesn’t seem be any changes to the features.