After migrating infrastructure to the cloud, it's imperative to test the disaster recovery plan (DRP) to ensure its effectiveness in the new environment. Without evidence of DRP testing post-migration, the organization cannot be certain that it can recover and continue operations during a disaster. While updating the DRP and configuring redundancy are essential steps, their effectiveness can only be validated through rigorous testing. Retaining previous infrastructure is less relevant if the cloud environment is properly configured and tested for disaster recovery. References: * ISACA CISA Review Manual, 28th Edition, Chapter 4: Information Systems Operations and Business Resilience.