2) init.d Support
1. Download this APK file and install it on your phone (Xposed Installer) HERE
2. Download this second app and install it on your phone (Xposed Tweakbox) HERE
3. Open the Xposed Installer and press Install/Update. Wait.
4. After installing the framework, press Soft Reboot. The phone will reboot and might boot longer than usual, dont panic
5. After the phone has rebooted, open the Xposed Installer again and go to the Modules tab.
6. Check Xposed Tweakbox. And exit the Xposed Installer.
7. Open the Xposed Tweakbox app and choose Miscellaneous from the menu.
8. Check Skip tracks with volume keys
9. Exit the application and reboot the phone
10. Enjoy !
NOTE: It works only when the screen is off (locked).