> We use POP3 message connection by outlook clients. Some people have outlook on their phone (iPhone in these cases) and outlook on their
> computer. Both are set to delete messages after 7 days when removed by the client. This is not working as messages removed over a month ago
> are still on the server.
Have you checked the diagnostics logs from Outlook to ensure that it is sending the DELEte commands to VPOP3?
A POP3 server doesn't delete messages unless an email client tells it to.
> As I understand going to vpop3 enterprise would permit IMAP4 access which would keep both clients in synch as removal by either is reflected on the other.
That is correct. IMAP4 is designed for having multiple devices connect to the same mailbox. All the mail is stored on the server, and the multiple devices simply show what is on the server. Also, multiple devices can connect at the same time, without conflicts. Note that if you do this, then you will probably need more storage on the server, because the whole mailbox is stored there, not on the email clients.
Using VPOP3 Enterprise, you can set up some users to use IMAP4 and have others continue to use POP3. For a specific user you should either use IMAP4 or POP3, because if you use a mixture, then POP3 clients will not be able to connect while IMAP4 clients are connected (and IMAP4 connections are usually long-lasting unlike POP3 ones, because new messages can arrive while the connection is in progress, unlike with POP3)
I hope this helps.