This option outlines a comprehensive change management strategy that prioritizes business continuity and security. Scheduling upgrades during off-peak hours minimizes the impact on users and critical operations. A phased rollout limits the potential "blast radius" of any unforeseen issues, preventing a network-wide outage. Backing up configurations is a fundamental best practice that ensures a swift recovery path if the upgrade encounters problems. Together, these steps form the most effective and least disruptive procedure for a significant system change like a data plane upgrade.

B: Performing a simultaneous, network-wide upgrade is a high-risk "big bang" approach that maximizes potential disruption, directly contradicting the goal of maintaining continuity if any issues arise.

C: Disabling security features, even temporarily, creates a significant vulnerability window. This action is fundamentally insecure and violates the core requirement of maintaining security during the process.

D: Performing upgrades during peak business hours maximizes the potential for operational disruption. This is the opposite of best practice for maintaining business continuity during planned maintenance.

1. Palo Alto Networks - Prisma Access Upgrades: The official documentation emphasizes minimizing disruption by allowing customers to choose their upgrade time. It states

"To minimize disruption to your users

select a time slot that is during your organization's off-peak hours." This directly supports the "schedule upgrades during off-peak hours" component of the correct answer and refutes option D.

Source: Palo Alto Networks

"Prisma Access Upgrades

" Prisma Access Administrator’s Guide. (Specific section: "Select a Preferred Upgrade Time Slot").

2. Palo Alto Networks - Best Practices for Content Updates: While this document is for content updates

the underlying principle of phased rollouts for risk mitigation is a universal best practice endorsed by Palo Alto Networks. It recommends staged rollouts to "a small group of non-critical firewalls" before a full deployment to limit the impact of a problematic update. This supports the "phased approach" concept in option A.

Source: Palo Alto Networks Knowledge Base

"Best Practices for Content Updates

" Document ID 52411. (Specific section: "Staging Content Updates").

3. Palo Alto Networks - Backing Up and Exporting Configurations: Official documentation consistently highlights the importance of creating backups before making significant changes to the configuration or software. This is a foundational step for disaster recovery and maintaining operational continuity.

Source: Palo Alto Networks

"Save and Export a Configuration Snapshot

" PAN-OS® Administrator's Guide. (Specific section: "Save and Export a Configuration Snapshot").