Microsoft has released the following updated SDKs for Microsoft Exchange Server 2010 SP1 Beta
Microsoft Exchange Server 2010 SP1 Beta Transport Agents SDK June 2010
Microsoft Exchange Server 2010 SP1 Beta Backup and Restore SDK June 2010
Microsoft Exchange Server 2010 SP1 Beta Web Services SDK June 2010
Microsoft Exchange Server 2010 SP1 Beta Backup and Restore SDK June 2010
Microsoft Exchange Server 2010 SP1 Beta Web Services SDK June 2010