Addon for Traveler's Backpack.
Four upgrades, one slot:
Put one in a backpack upgrade slot. That's the stack limit for storage in that backpack. Your hotbar and player inventory still cap at vanilla sizes.
You can swap to a different tier by placing it on top of the current one. Downgrading only works if nothing in the backpack is over the new limit. Same rule if you try to take the upgrade out.
Requires Traveler's Backpack. Stacc is bundled so counts above 127 actually save and sync.
