What is necessary for documenting the classification level during upgrades?

Documenting the classification level during upgrades requires a revised security classification guide. This is essential because a revised guide integrates new information and reflects changes in classification criteria, ensuring that the updated classification level is in alignment with current standards and guidelines. It provides a formal, authoritative source that outlines how to treat and label the information after the upgrade, which is crucial for maintaining proper security protocols and compliance with regulations.

In contrast, simply having a notice of changes would not sufficiently provide the comprehensive context or rationale needed for making classification decisions. Relying solely on a current classification guide without revising it may lead to outdated or incomplete information being used. Keeping track of all previous classifications is important for historical reference but does not address the immediate need for a clear and accurate classification level post-upgrade. Therefore, the revised security classification guide serves as the foundational document necessary to maintain the integrity of the classification process during upgrades.