Migration Checklist: Employee Data System Transition

1. Overview

Risk Level: Critical (High impact on payroll, tax compliance, and data privacy).
Timeline: 12 Weeks (Recommended).
Team Size: 4-6 members (Project Lead, IT Admin, HR Lead, Data Protection Officer, Finance Lead).

Define project scope and identify all data entities (PII, salary, tax codes, bank details).
Appoint a Data Protection Officer (DPO) to oversee the Data Protection Impact Assessment (DPIA).
Create a comprehensive inventory of current integrations (e.g., pension portals, HMRC gateways).
Establish a migration steering committee with weekly status reporting.
Identify 'orphan' accounts or inactive employee records that do not require migration.
Conduct a gap analysis between legacy fields and new provider data structures.

Standardise date formats across all legacy CSV/SQL exports to match the target schema.
Sanitise PII; remove duplicate entries and resolve conflicting addresses or contact details.
Map legacy custom fields to the new provider’s API endpoints.
Validate National Insurance (NI) number formatting for all active employees.
Perform a test import of a dummy dataset to verify field mapping accuracy.

Execute a full, encrypted backup of the legacy database to a secure, offline, UK-based server.
Verify the integrity of the backup using checksum validation.
Store the backup in a WORM (Write Once, Read Many) environment for audit longevity.
Generate an encrypted manifest of all files included in the golden copy.

Document all API keys and OAuth tokens currently in use.
Verify if the new provider supports existing SSO (Single Sign-On) providers (e.g., Azure AD/Okta).
Review HMRC RTI (Real Time Information) submission compatibility.
Audit existing payroll schedules to ensure they align with the new platform’s processing cycles.

Communicate the "Freeze Period" dates to all staff, prohibiting changes to personal details.
Configure SMTP relay settings for automated payroll notifications.
Disable write access to the legacy system to prevent "delta" data changes.
Finalise the Data Processing Agreement (DPA) with the new vendor.
Set up user roles and permission hierarchies in the new environment.
Whitelist the new provider’s IP ranges in the corporate firewall.

Execute the final data extract from the legacy system.
Run the automated ingestion script for bulk employee record migration.
Perform a transformation check to ensure currency values (GBP) migrated without rounding errors.
Manually migrate high-sensitivity records (e.g., disciplinary notes) that require restricted access.
Validate user account provisioning via SCIM or manual upload.
Monitor API error logs for rejected records or schema mismatches.

Establish a 24/7 support desk for the first pay cycle post-migration.
Implement a hyper-care period (first 2 weeks) for resolving urgent access issues.
Configure automated backup routines for the new system.
Set up alert triggers for failed payroll syncs or API timeouts.
Review performance benchmarks against the legacy system's latency.

Securely wipe the legacy environment according to the agreed data retention policy.
Provide proof of data destruction (Certificate of Erasure) for audit logs.
Archive the Golden Copy in a restricted-access, encrypted vault.
Revoke all API keys and service accounts associated with the legacy provider.
Update internal IT knowledge base articles with new system navigation paths.

Host a "Lessons Learned" meeting with the migration team.
Document deviations from the initial project plan.
Update the Business Continuity Plan (BCP) to include the new provider's recovery procedures.
Circulate a feedback survey to employees regarding the new UI/UX.

Update the Privacy Notice to reflect the change of data processor.
Confirm the new provider stores data within the UK or an EEA-adequate country.
Ensure Standard Contractual Clauses (SCCs) are in place if data leaves the EEA.
Validate that the new provider allows for "Right to Erasure" (Right to be Forgotten) requests.
Implement technical measures for data pseudonymisation for reporting purposes.
Document the legal basis for processing for each data category.
Verify the new platform provides automated logs for Subject Access Requests (SARs).
Ensure the new system supports granular access controls to prevent data over-exposure.

Issue: Character Encoding Errors. Action: Ensure UTF-8 encoding during CSV export/import.
Issue: API Rate Limiting. Action: Implement batching logic to stay within provider limits.
Issue: Failed Authentication. Action: Check SAML certificate expiry and metadata sync.
Issue: Data Truncation. Action: Review field length limits in the new UI schema.
Issue: Payroll Discrepancy. Action: Recalculate tax codes manually for the affected records.