Access to Cisco DNA Center CLI is required when upgrading the Cisco DNA Center software. The CLI provides a direct interface to the underlying system, allowing for detailed control and monitoring of the upgrade process. It is essential for executing commands that may not be available through the graphical user interface (GUI), ensuring a precise and controlled software upgrade. References: The official Cisco documentation outlines the procedure for upgrading Cisco DNA Center software via CLI, detailing the necessary steps and precautions to take during the process