Game NFTs of structures and equipment can be upgraded. Either rarity or level of the card can be upgraded.
The game NFT in the DeepMine universe are divided according to:
Upgrade by rarity
Type of use: structure, equipment, badge.
Development level: 0-9 level inclusive
Some types of NFT have rarity that is highlighted by their color:
A Citizen sends three cards identical by type, rarity, and level to the Government. In return, the citizen receives one NFT with a higher rarity.
Upgrade by level
The player must send a certain amount of DME, a card to be upgraded, the upgrade card and also fulfill additional conditions to upgrade the card by level. In return, the citizen receives a card of the same type and rarity, but a higher level.
Additional conditions for the mine:
The Mine owner must have the abilities and skills to transition to more dangerous Depths and upgrade a mine to the next level. Therefore, the mine must mine a certain amount of DME for a certain period of its operation for the upgrade.