Through a number of Technical Change Workshops, it was identified that different messages within the CSS design had different capitalisation requirements for the word MPID. In particular, it was highlighted that ‘mpId’ contains upper case ‘I’ for the ‘mpId’ in the ‘Supplier Arranged Appointment Update Notification’ message which differed to other message requirements within the CSS. Investigation by the CSS Provider has confirmed that this is the correct configuration of the system, and it was agreed that the solution would be to provide an explanation within the PhiD of the capitalisation requirements. The document has been updated by the CSS Provider to reflect this clarification and has been shared within TCW attendees for review, the members were happy with the updates.