This article breaks down exactly what that means, why Update 1.2 is critical, how the "World" edition differs from other CIAs, and how to achieve a truly portable experience.
The (approximately 539 blocks or ~67MB) is a stability-focused patch primarily aimed at fixing game-breaking bugs in competitive play. While it does not add new features, it is required for all online functionalities. Version 1.2 Key Improvements pokemon ultra sun update 12 3ds world cia portable