From the announcement:
Since its successful debut in 2014, Akrotiri designers Jay Cormier and Sen-Foong Lim have converted the feedback they received from the game’s many fans into several improvements that can be seen throughout the revised edition.
Originally conceived as a multiplayer system, the original version of the game was eventually refined to become the strategic 2-player affair it is known as today. Now players can experience “multiplayer Akrotiri” with the revised edition. With two copies of the game, up to four players can join in the search for legendary temples.
By combining all components from one copy of Akrotiri with the drachmas from another, additional players will be ready to launch their own expeditions. Furthermore, to differentiate from previous printings, the new edition contains player components in new colors.