There are some new requirements for certain business types and some requirements have been removed. In addition, many of the existing requirements now include new controls. What will change for your business depends on your SAQ (Self-Assessment Questionnaire) type.
How these changes impact you will be determined by your Self-Assessment Questionnaire SAQ type. The portal journey has been updated to ensure that all changes have been factored in, to ensure that you are reporting against version 4.0.