You are the enterprise IT transformation lead. Create a comprehensive, stepwise masterplan for migrating from Windows 10 (EOL) to Windows 11 across [Organization/Department/Number of Devices] by [Deadline], including all business-critical and complex software used in your environment. Your plan must cover:

Executive summary (timing, support, risks of delay)

Stakeholder mapping (business, IT, InfoSec, software owners, power users, vendor contacts)

Detailed asset and software inventory (hardware specs, installed apps, versions, license status, business owner, mapped per device)

Application criticality assessment: Classify each major app as: Essential, Regulated, Legacy/Unsupported, High-Availability, or Non-Critical.

Compatibility testing: For each Essential or Regulated app, document vendor Windows 11 support status, required upgrades, and last successful UAT version; escalate unsupported/at-risk apps to vendor, legal, or risk committees.

Risk register: List known app risks (e.g., unsupported software), mitigation plan, fallback/workaround, and owner.

Pilot planning: Design a phased pilot with users of complex/regulated software; include rollback criteria and pilot feedback forms.

Phased deployment schedule (pilot, power users, main cohort, exceptions), with timeline and sample user communications

User and support readiness: Update helpdesk scripts, create custom end-user guides for high-risk apps, IT escalation matrix for critical failures

Third-party vendor engagement: Contact software vendors for roadmap/patch info; document SLAs, open tickets, and remediation timelines

Compliance & security: Regulatory and data privacy checks for regulated apps, test device encryption, remote management, and role-based access control

Change management: CAB approvals, user sign-off forms for successful upgrade, tracking of exceptions

Monitoring and KPIs: Track migration status by device/app, open app issues, helpdesk volumes, user NPS, business impact; set thresholds for escalation

Executive and board reporting: Weekly update slide, issue log, next steps, and outstanding software risks

Post-migration validation: Confirm all business-critical apps work as intended (with documented user signoff), lessons-learned log, vendor feedback survey
Each section must be clearly labeled, with actionable tables, checklists, sample emails/scripts, and escalation steps for at-risk software. Do not include software examples—users must provide their own list.