Google does not seem to have any sort of unified or even consistent strategy when it comes to their many apps that can do the same thing. In some cases they continue to release new apps that seem to compete with each other, like what Google has done in the instant messaging space with several clients for users to choose from. Meanwhile, in the music player space, Google appears to be on track to consolidate things under the YouTube banner and will eventually abandon the Google Play Music app as a separate platform. A new update to the YouTube Music app adds another small piece toward making that a reality.
Google has an update to YouTube Music to bring it up to version 2.21 that includes code to implement a Play Music feature. As part of the update, Google is adding a setting so that users can select what kind of quality they want streaming audio played at depending on the kind of network used. Options for networks include WiFi, cellular or mobile networks, and indirectly downloaded music that is stored on a device. For these different options, users can choose whether they want lower quality, normal quality or high quality streams. This would impact both the amount of data used as well as the likelihood of buffering occurring. The settings for WiFi and cellular are new in this update. The settings for downloaded music already existed in the app, but are located in the settings for playback of music videos.
All of these settings and options have existed in the Google Play Music app, which has seen updates whither to being almost nonexistent. Sources believe the presence of features and functions from Play Music that end up getting ported over to the YouTube Music app are a sign that Google is working toward deprecating the Play Music platform in favor of the YouTube Music app and platform.
If you want to give version 2.21 of the YouTube Music app a try, you can download this version with this additional code using the APK Mirror link below or install version 2.19 from the Google Play Store and wait for your device to receive the update via Google.
Download It Now: Play Store
Download APK Now: APK Mirror
source: Android Police