An IT risk register is a document that records and tracks the IT risks that have been identified and assessed by the risk practitioner. It contains information such as the risk description, the risk owner, the risk level, the risk response, the risk status, and the risk monitoring and reporting activities. An IT risk register is a dynamic document that needs to be updated regularly to reflect the changes in the IT environment and the risk landscape. When a software upgrade renders an existing key control ineffective, the risk practitioner should update the IT risk register to indicate the new risk level, the new risk response, and the new risk monitoring and reporting activities. This will ensure that the IT risk register remains accurate, relevant, and useful for IT risk management. Updating the IT risk register is more important than updating the audit engagement letter, the risk profile, or the change control documentation, because the IT risk register is the primary source of information and guidance for managing IT risks. The audit engagement letter is a formal agreement between the auditor and the auditee that defines the scope, objectives, and terms of the audit. The risk profile is a summary of the organization’s risk appetite, risk tolerance, and risk exposure. The change control documentation is a record of the changes that have been made to the IT systems and processes. These documents are important for IT risk management, but they are not as critical as the IT risk register for updating when a key controlbecomes ineffective. References = Risk and Information Systems Control Study Manual, Chapter 2: IT Risk Assessment, Section 2.4: Risk Register, pp. 69-711