This change was necessary to fix the problem created by the original HD 1.5 ReMIX, wherein by changing Sora's special attacks to be bound to Reaction Commands, or, it would also inadvertently call his party members for help with the same input.
Kingdom Hearts HD 1.5 + 2.5 ReMIX, stylized as Kingdom Hearts HD I.5 + II.5 ReMIX, is a compilation game comprised of Kingdom Hearts HD 1.5 ReMIX and Kingdom Hearts HD 2.5 ReMIX for the PlayStation 4, Xbox One, PC via the Epic Games Store, and Nintendo Switch as a Cloud version.