Data migrations in distributed system

We have two bounded contexts: one for displaying analytic data using widgets and second one for managing data source that widgets display.

So we have the DashboardAggregateRoot that holds the UI meta data and the list of Widgets. Each Widget is linked to configured data source.

Data source bounded context knows nothing about dashboards and widgets. It's responsibility is to configure data source.

So we have two views in UI:

1. UI for configuring dashboard (and nested widgets). If you select widget you can then configure it's data source in separate view
2. Separate view for data source configuring for selected widget

How should we store the meta of configured data source in Widget? How we should handle data migrations? (We have two services: one for UI and another for DataSource. Moreover these two service are so complex, so each service is being implemented by different team)