I read this answer and undestood why I should keep names of my services, activities, and custom views. But should I keep my classes which derive from android.support.v4.app.Fragment?
I also took a look at the defualt Proguard config file
The main reason why you would need to keep a
class, is because it is accessed via reflection.
Fragments are normally not accessed via reflection, so you don't have to keep them.
Except if you reference them directly in layout files (because parsing layout files uses reflection).