Matt Stehle, a Microsoft Support Engineer as a nice post about messaging development, where he points out the new features of Exchange 2007 and also the discontinued features and de-emphasized functionality.
Discontinued Features and De-Emphasized Functionality
http://www.microsoft.com/technet/prodtechnol/exchange/e2k7help/79df6a3a-29a8-4935-b143-8a66c8d082d4.mspx?mfr=true
Here are the development features that are discontinued…
APIs and Development Features
• Transport event hooks: Retain a computer that is running Exchange 2000 or Exchange 2003 in the Exchange 2007 organization if you need this functionality.
• Workflow Designer that was included with the Exchange 2003 SDK: Use Windows Workflow Services (WWS).
• Collaboration Data Objects (CDO) for Workflow that was included with Exchange 2003: Use Windows Workflow Services (WWS).
• Microsoft Collaboration Data Objects for Exchange Management (CDOEXM): Retain a computer that is running Exchange 2000 or Exchange 2003 in the Exchange 2007 organization if you need this functionality.
• Exchange Windows Management Instrumentation (WMI) classes: Retain a computer that is running Exchange 2000 or Exchange 2003 in the Exchange 2007 organization if you need this functionality.
• MAPI client and CDO 1.2.1 on the Exchange installation: Exchange 2007 no longer depends on these components. They are a separate component that will be available for download. For more information about how to download the required components, see MAPI client and CDO 1.1.2 and CDO, version 1.2.1.
Here are the development features that are de-emphasized…
There are legacy Exchange features that are now being deemphasized in Exchange 2007:
• Public folders – Free/busy calendaring functionality is provided by the Availability service. If you need additional functionality, migrate to SharePoint Portal Server or a similar product.
• Proxy address generators – Use the Exchange Management Shell.
• CDO 1.2.1 – This functionality is provided by the Exchange Web Services.
• MAPI32 – This functionality is provided by the Exchange Web Services.
• CDOEX (CDO 3.0) – This functionality is provided by the Exchange Web Services.
• Exchange WebDAV extensions – This functionality is provided by the Exchange Web Services.
• ExOLEDB – This functionality is provided by the Exchange Web Services.
• Store events – This functionality is provided by the Notification Web service.
• Streaming backup APIs.
• Exchange 2003 Virus Scanning Application Programming Interface (VSAPI).”
Keep in mind that de-emphasized features will still be supported to work on or against Exchange 2007 but we will strongly discourage you from writing new solutions that use these APIs.
New Development Functionality
http://www.microsoft.com/technet/prodtechnol/exchange/e2k7help/79df6a3a-29a8-4935-b143-8a66c8d082d4.mspx?mfr=true
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