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Unique identifier for this plan version change.
The ID of the plan being migrated.
When the migration takes effect. Can be a specific date/time, 'end_of_term' when scheduled to be at the end of the current billing period, or 'end_of_invoice' when scheduled to be at the start of the next invoice.
Current status of the migration: 'not_started', 'in_progress', 'completed', 'action_needed', or 'canceled'.