--- a/net/minecraft/world/inventory/ContainerListener.java
+++ b/net/minecraft/world/inventory/ContainerListener.java
@@ -6,4 +_,10 @@
     void slotChanged(AbstractContainerMenu containerToSend, int dataSlotIndex, ItemStack stack);
 
     void dataChanged(AbstractContainerMenu containerMenu, int dataSlotIndex, int value);
+
+    // Paper start - Add PlayerInventorySlotChangeEvent
+    default void slotChanged(AbstractContainerMenu containerToSend, int dataSlotIndex, ItemStack oldStack, ItemStack stack) {
+        slotChanged(containerToSend, dataSlotIndex, stack);
+    }
+    // Paper end - Add PlayerInventorySlotChangeEvent
 }
