When using the feeding upgrade on the backpack, it does not feed water to the player, only food. Additionally, the water bar gets reset to full when the feeding upgrade feeds food to the player, defeating the point of drinking water at all. I understand how it may be difficult to add support for different water purities (dirty, slightly dirty, etc), but at the very least, I'd like to see the water reset bug get fixed.

I just tested this and I'm not sure if it's entirely backpack's fault. The item selected to thirst check if minecraft:air, but it somehow still returns value of 8, which causes every food that feeding upgrade uses to replenish thirst.

I'd suggest reporting this to the Thirst was taken dev to return 0 if the item is invalid

public static int getThirst(ItemStack itemStack) { Item item = itemStack.getItem(); return VALID_DRINKS.containsKey(item) ? ((Number[])VALID_DRINKS.get(item))[0].intValue() : ((Number[])VALID_FOODS.get(item))[0].intValue(); }

here