When you use delegates in Outlook 2007, it is recommended that the manager and all the delegates use Outlook 2007 Service Pack 2

When you use delegates in Outlook 2007, we recommend that the manager and all the delegates use the same version of Microsoft Office Outlook (specifically, Office Outlook 2007 Service Pack 2). The manager and the delegates are not prevented from running mixed versions of Outlook in an Outlook 2007 Service Pack 2 (SP2) environment. However, we strongly recommend that such an overlapping period be kept as brief as possible.

In earlier versions of Outlook, such as Outlook 2003 and Outlook 2002, the manager and the delegates can use different versions of Outlook. For example, the delegates can use Outlook 2002, and the manager can use Outlook 2003. However, we do not recommend this configuration.

Although Outlook 2007 does not disable the functionality that lets the manager and the delegates use different versions of Outlook, we recommend that the manager and all delegates use Outlook 2007 SP2 or later. By doing this, you improve calendar reliability. We recognize that users who cannot upgrade to the same version of Outlook at the same time may have to run mixed versions of Outlook. However, you should limit such a mixed-version topology to a short time during an upgrade period (approximately two months). If you encounter calendar reliability issues, deploy Outlook 2007 SP2 for the manager and for all delegates as your first troubleshooting step. Then, determine whether the issue continues to occur before you take additional troubleshooting steps.

If either the manager or the delegates use Microsoft Entourage 2004 for Mac version 11.3.0 or a later version, you can have a mixed manager-delegate topology. For more information about the Microsoft Office 2004 for Mac 11.3.0 Update, click the following article number to view the article in the Microsoft Knowledge Base: Note Entourage clients cannot connect with a Microsoft Exchange Server 2007 mailbox for delegate rights assignment unless public folders exist in the Exchange 2007 organization. If public folders do not exist in the Exchange 2007 organization, use one of the following workarounds:

• Add a public folder store to the Exchange server. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
  924625  (http://support.microsoft.com/kb/924625/ ) When you use Outlook with an Exchange 2007 mailbox, you cannot connect to Exchange 2007, and you receive an error message
• Move both the delegate and the manager to Outlook 2007 SP2 or later. Outlook 2007 does not require public folders in order to access an Exchange 2007 mailbox.