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# Overwriting campaign_id and outreach_id

We've started writing over the `campaign_id` or `outreach_id` values on [Orders](/developer/marketing/api/ecommerce/list-store-orders) to align with [our new attribution model](https://mailchimp.com/help/about-mailchimp-attribution/) and user-configured settings. If your integration is sending `campaign_id` or `outreach_id` with [Add Order](/developer/marketing/api/ecommerce/create-store-order) or [Update Order](/developer/marketing/api/ecommerce/update-store-order) API calls, we recommend deprecating that logic.

We’re rolling out [Mailchimp's native attribution model](https://mailchimp.com/help/about-mailchimp-attribution/) across all e-commerce integrations. This new model gives you more complete insights into how marketing campaigns contribute to customer purchases. It also improves marketing performance reporting for all Mailchimp customers using e-commerce integrations. Additionally, this reduces the need for complex custom logic for attributing orders to specific marketing messages.