Hi All, Ifresh installed exchange 2007 and created some mailbox for daily operation. Due to some reason, I need to downgrade to use Exchange 2003. Can I join exchange 2003 in exchange 2007 environment for mailbox migration? Thank you. Ray

Hello Ray, I think you can install Exchange 2003 in Exchange 2007 environment since new version of product supports older in environment but you need to configure the mail flow between Exchange 2003-2007 servers by creating Routing Group Connector manually & can not use Outlook 2003 clients if you have selected that you dont have any legacy outlook clients in environment during Exchange 2007 setup. How to Create Routing Group Connectors from Exchange 2007 to Exchange Server 2003

Hi, After you deploy a new native Exchange 2007 organization, you can't add servers that are running earlier versions of Exchange to the organization. The addition of earlier versions of Exchange to an Exchange 2007only organization is not supported. For your reference: http://technet.microsoft.com/en-us/library/aa998604(EXCHG.80).aspx Mike

Hi Mike, Thank you. BR Ray

Technically you can, but you need to remove Exchange 2007 from the environment and then clean up the AD environment using ADSIEdit. This involves removing all the Exchange 2007 objects from AD.

see my post here: http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3630252&SiteID=17 it works fine if you do what bardpony says.