Some ESN rubbers are max+ (for example Donic Bluestorm, Tibhar Aurus Prime/Select, i. e. most of the rubbers that have the thick sponge/thin topsheet technology), and the sponge in this case is 2,33 mm thick.
However the Omegas VII are "regular" rubbers, which means that "max" indeed is (most likely) 2,3 mm.