If you open the section where you are using this DynamicSelect control, you can see the Update Controls button through which you can update the deprecated controls to the latest used controls as shown in the attachment.
In Pega7 we have DropDown control which replaced DynamicSelect control functionality.
The Pega 7 Upgrade Accelerator Pack, formerly the ECS Upgrade Utilities, is a set of tools that help you to migrate your PRPC instance to the Pega 7 Platform. The tools automate the task of identifying and upgrading deprecated features so that you can use the latest features.
This helps in "Upgrade Deprecated UI Components and old FlowActions" task for your application in Bulk. FYI, i had tried this utility at my local as shown in the attachment and it also has many other features as explained in the above link.