Your requirement is to migrate the Contact Roles for Opportunities. But you do not find the options in the Migration of Opportunities template.
Opportunities migration template does not contain the Contact Role field. Further, there will not be any new enhancements for old migration templates.
It is recommended to use the Data Workbench approach to upload the Contacts and its Roles to the Opportunities. You may use the service Opportunity Prospect Contact Party Information.
The Data Workbench workcenter and its views are not accessible in Silverlight client. It is accessible in HTML5, and the system allows these actions from HTML5 client only. This is the system behavior.
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