Interface Changes Impacting the Data Types and Long Running Instances

Hi Team,

I have new requirement to add few fields in the interfaces for which i updated the existing interfaces and data types. But there are many active instances available in production which might cause issue?

In One Scenario i want the latest changes also to be included after the deployment and in another task i want the hide the latest changes for few tasks.

Can you please guide me to the list of steps that i need to take care while moving the changes to Production.

Please let me know if any further information is required