Based on google docs beginning with Android 4.4 (API level 19) Android apps doesn't need WRITE_EXTERNAL_STORAGE Permission to write to its own application-specific directories.
uses-permission
So I removed this permission for API 19:
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"
android:maxSdkVersion="18" />
But after publishing app, we find out some android devices(not all of them) with API > 18 have problem and app can't write to it's own application-specific directories.
I remove android:maxSdkVersion and published app again and problem solved.
How is that possible?
And what I should do to remove this permission and my app work in all devices?