Plant upgrade system (Chinese version)

In the Chinese version of Plants vs. Zombies 2, plants can be leveled up via puzzle pieces and coins. Leveling up a plant gives it new abilities. Before the 1.4.0/1.4.1 update, level 3 was the maximum level. After the 1.4.0/1.4.1 update, level 4 became the maximum level.

Trivia

 * Some plants cannot be leveled up (e.g. Power Lily, Sun Bean, Lily Pad, etc.).
 * Spikeweed, Spikerock, Cherry Bomb, Jalapeno, Iceberg Lettuce, and Potato Mine can only be leveled up to a maximum of level three after the 1.4.0/1.4.1 update.
 * For Cherry Bomb and Jalapeno it's because they are instant use.
 * For Spikeweed, Spikerock, Iceberg Lettuce and Potato Mine it's unknown.
 * Zombies can also level up, however, the player cannot control this and it only increases the zombies' health and damage they cause to plants.
 * In the files, there is an unused red border for the seed packets, although it is unknown what it does.
 * The red border has been hacked in by some hackers and is for an unused Level 5 tier.