How to restrict users selecting past iterations in "Planned For" attribute
One answer
Option 1) Archive the Iteration. Archive button is only available in the web client.
Option 2)
Create Iteration type "Completed" and remove all permissions for this iteration type. All permissions for this Iteration type is unchecked.
Whenever an Iteration is completed, change its type of "Completed" and user would not be able to save any work item for that "Planned For".
Option 2)
Create Iteration type "Completed" and remove all permissions for this iteration type. All permissions for this Iteration type is unchecked.
Whenever an Iteration is completed, change its type of "Completed" and user would not be able to save any work item for that "Planned For".