Office 2003 user needs to see To Do List and Emails that are Flagged from Office 2013 User

Hello,

I have a user on Office 2003 who needs to see the To Do List and Emails that have been flagged (from someone who is using Office 2013).  On the Office 2013 PC, I set the permissions for the Office 2003 user to be Author to Everything.  Is this an incompatibility issue?  Im thinking that Office 2003 may not have the same Flag Email features as 2013.  The To Do List seems to be specific to Office 2013.  Someone please help--  ask questions if need be; I tried to explain this situation the best that I can. 

THANK YOU!