I have a System Field "Release" of type 'String' in the Requirement module and have to add this field in the 'History' [audit trail] for requirements, But the problem is 'History' checkbox in the Project Entities is disabled, I can not checked it to make this field addition to the Requirements history.

Is there any way through which I can enable this 'History' checkbox?
or any another way through which I can add this field to the Requirement's history?

Can anyone guide me on this situation?