[paras chugh]

The question's clear

[ULOP3Z]

To fix bugs faster

[loofmodnar]

It could be that they needed new/expanded APIs to implement that stuff. This could be a case where MS is dogfooding some new app development method and the Xbox Music team hit on a bunch of issues with it that needed the OS update to fully resolve them. That would potentially explain why stuff like displaying the list of artists is so painfully slow in XBM but works fine in many other apps.