I am preparing to move our production Cisco Network Services Orchestrator from the current 5.x release to 6.5 and would like an experienced NSO engineer to guide the entire upgrade lifecycle. Scope – Installation & initial environment setup: help me plan prerequisites, perform the in-place/side-by-side install, and verify system services start cleanly on 6.5. – Configuration migration: craft and execute the migration strategy so all CDB data, packages, Yang models, NEDs and custom Python/Java code compile and behave exactly as before. – Testing & validation: design smoke and regression tests, run them with me, tune any performance hits, and produce a concise rollback plan if issues appear. Environment details and access methods (SSH, Ansible, GitLab) will be shared once we agree on the approach. I am comfortable handling routine CLI work; I mainly need your expertise on best-practice sequencing, hidden “gotchas” between 5.x and 6.5, and troubleshooting during live cut-over. Deliverables • Step-by-step upgrade run-book (Markdown or Word) • Script snippets or playbooks you write or modify • Post-upgrade validation report confirming service packages, NEDs and APIs operate normally Acceptance Criteria The platform boots on 6.5 with no critical alarms, all services can be provisioned and deleted through NSO and external northbound integrations, and the rollback plan is validated. If you have completed similar NSO 5.x → 6.x migrations, please outline the most significant challenges you solved and the tools you prefer (e.g., ncs-cli, Python, Docker, Ansible). I am ready to start as soon as we align on the schedule.