Islebound: Emerald Edition is a special edition of the game with some altered components and rules. It's best to think of it as a variant of the game, rather than a 2nd edition. 

This edition of Islebound removes the book resource from the original game and replaces it with emeralds. Emeralds have different uses than books. You collect them when visiting a player-owned town and when you take over a town. Emeralds must be used to buy building cards, and they can also be used to perform special abilities, such as keeping pirates and serpents after combat! The building deck is revised to account for this resource change. It includes altered building cards from both the original game and some from the Metropolis expansion. There will not be a building card expansion for Islebound: Emerald Edition, and the Metropolis expansion is not compatible with this version.

The backs of the crew tiles can be used in Above and Below.