The RACF® common command exit, IRREVX01, allows customers to customize or cancel RACF commands before the RACF command processor is invoked. This exit is the recommended vehicle for preprocessing RACF commands. Before RACF provided this exit, some customers created their own front-end processors to preprocess RACF commands. Because RACF 2.2 changed the way RACF processes commands, customers who wrote front-end processors before RACF 2.2 and who want to continue to use these front-end processors might have to change them. This information is intended for those customers.