Okay, it can be closed, after installing another ADB Driver it worked

@wgarcia Thank you !

@Chim Hi and welcome! I don't know what type of files plays the Music Player, but you can convert the files to the format that is playable. Regarding the version: if you are on stable and no OTA updates are available than you're good. You can check that in Settings/Updates/Update settings and change to RC, dev or stable accordingly.