Scheduled Service Change: Move BES Service Account Mailbox to Exchange 2010
Users trying to check their BlackBerrys at midnight Sunday evening may experience a delay in receiving and sending mail.
There is no workaround for this issue
On Monday August 1st at 12:00am the CIT Exchange Team will be moving the BlackBerry Enterprise Server Service mailbox from Exchange 2007 to Exchange 2010. This will enable the BlackBerry Enteprise Server to provide service to Exchange 2010 users. Exchange 2007 users should see no effect other than a short delay in sending and receiving mail from BlackBerry devices during the mailbox move.