Useful or like button on review

I have found that useful or like button is working using ip but not user_id. But it is not good for a site. Because now a days shared ip is being used a lot. How to achieve the like option according to user_id.

Another important thing is that when someone is not logged in then a message shown is that- “You must be logged in to post a comment” Rather it should be “You must be logged in to post a review”

I’m using latest geodirectory, whoop theme and all geodirectory addons.