Can I change the default music player app on my iPhone? If so, how? I want to change the default music app on my iPhone from Music to Spotify. Is this possible?  My first guess is that I would have to jailbreak my phone. Is there anyway to do it without jailbreaking?
Uninstall the default music app in iOS 11.
Restart. voila. 

My headphone control now works with wynk music app.
control center also shows wynk music.