Retrieve older massages from mail server

[Demonweare]

I switched from Outlook 2003 to 2007 and replaced new data file (.pst) with
back-up one. Outlook already downloaded a bunch of emails but, obviously,
lost them when data file was replaced with back-up.

How do I get Outlook to retrieve messages again?

 

[dlw]

When you say you "replaced" the new pst with the backup, do you mean deleted,
over-wrote? If that is the case, and outlook was set to *not* leave a copy
of the messages on the server, they are gone. If the new pst is still
somewhere, you can do a File>open>outlok data file and find the messages
there.