Forum Different Message Editting Permissions
 

From the settings->options menu, I set the message editting time limit as 60mins for all users.

But, for some users in my forum I need to give them permission for editting older posts. Because they publish some news and articles and they need to update them from time to time.

So, how can I give them unlimited message editting permission without giving them moderator privileges? I just want them to have unlimited message editting permission. But no other difference from a regular user.