Production upgrade: This requires Grand Theft Auto operation. When your key skills are low, you need to use advanced raw materials to make a cross-level key. For example, if the player's current key is 1 level, then use the production materials of level 2 key to operate. In this way, there is a certain chance to get the upgrade key, that is, the advanced key. Generally, the second to third grade raw materials are inexpensive and easy to collect, which is suitable for most players to choose and operate.
Synthesis upgrade: If there are many low-level keys in the game, you can choose to use them for synthesis upgrade. There is a certain probability that three low-level bonds can be combined into a high-level bond, and the probability of synthesis is about 30%, which is neither high nor low. You can choose to operate in the synthesis interface, or you can choose to find NPC synthesis operation in the jewelry store.
NPC upgrade: This method is similar to goodwill games, but only limited to professional operations in Grand Theft Auto. After the player finds the thief, he keeps giving gifts through interactive games. Note here that gifts only look at quantity, not rarity. So use low-level props. After giving a lot of props, thieves can help players upgrade their low-level keys. There is no limit to the number of upgrades, but there is a time limit. Players should be prepared before operation.