The special shop interface. The bag currently has 89 spaces.
The special shop is a shop that is accessible from the help menu, directly below regular shop. This shop allows you to upgrade the storage for your backpack. You may also upgrade your loot and pet space. The upgrades will increase your available inventory by 1 for every upgrade. The upgrades initially cost 1 million for the loot and 5 million gold for the pets to upgrade. The cost of upgrading increases each time. The maximum amount of spaces for pets is 20, and for loot is 100. Although, if you have very fast reflexes and a lot of spare money, you might be able to get in an extra click before the game realise you're above the cap, allowing for 21 pets and 101 equipment storage space.
The maximum amount of drops is now 101.