Use APKPure App
Get HandleExternalStorage old version APK for Android
Enables read and write access to the external storage for all apps
Enables read and write access to the external storage for all apps.
IMPORTANT
This app has no user interface. Enable it in Xposed - reboot - done.
IMPORTANT
Your device has to be rooted to install the required X-posed framework: http://tinyurl.com/cd46qco