Per our client request, I am looking for a function to Delete or purge email in Inbox/Spam/IMAP Folder which older than (1,3,5,7,10,30,60,366 days) etc.  This function is shown in directadmin, so I believe it's only a script to handle it. 

For the way to apply in iredadmin,

1. Add a button to execute the script in User page
2. Create a script to delete the select Maildir by date. 
find /var/vmail01/vmail/<$USER DIR PATH>/Maildir/cur* -mtime $DAY -exec rm {} \;
find /var/vmail01/vmail/<$USER DIR PATH>/Maildir/new* -mtime $DAY -exec rm {} \;

Please let me know if I am on the right path.  Thanks.