{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"The backup operations before blockchain upgrading include the following contents:","a":"State database backup: The state database contains the balance of all accounts in the blockchain network and the status of smart contracts. Backing up  the state database ensures that the network can be smoothly operated after the upgrade."}]}],"pr":"e6bd4da5b06144f2cbc830ce278734c90e510dc8f9fa21a45c7347c202cd5fd3"}