Combine apples, sugars, salt, and cinnamon in a bowl and mix well. Place in the bottom of a slow cooker bowl that has been greased/sprayed or lined with parchment paper.
Mix topping ingredients well and sprinkle over apple mixture in the bowl.
Cook on low for 4 hours. Halfway through cooking time, give the contents a stir.
Turn off the heat and let sit for an approximately half an hour to cool a bit.