You might have noticed that in newer updates, the game will also display its sub-version in the GAME START screen.

Offline - Ensures the smoothest experience with the game, but does not have any online modes exclusive to Main sub-version. (Duel mode is still available if you're connected to the Internet)

Shunt - Basically Offline sub-version but hosted online.

Main - Has additional online features and game modes (like register/login, cloud saves, level hub in Level Creator, Skill Tournament game mode, etc.). The only server of the Main sub-version is at https://pvz.jiangnangame.com/play/index.html . Go there to experience new features and game modes exclusive to the Main sub-version.