Preheat oven to 375 degrees.
In a large bowl, stir together sugar, flour and lemon rind.
Add apples, blueberries, raspberries, and cranberries, stirring gently to combine.
Spoon into 13 by 9-inch baking dish.
TOPPING:
In a small bowl, stir together oats, sugar, flour and cinnamon.
Drizzle with butter and toss.
Spoon over fruit.
Bake in until filling is bubbly and topping is golden brown.
Serve warm or at room temperature.