About: CDO 1.21

  • Article

API Interface: Mailbox AccessorAPI Interface: COM Library with no custom interfaces (IDispatch only)
Business Logic: Messages, AddressBook, and default mailbox Calendar.
Language Support: Any *unmanaged* COM compatible language (C++, VB6, VB Script).
Direct Property Access: Yes.
Product Versions: All versions of Outlook and Exchange up to 2003. Also available for download.

Description:

 

CDO 1.21 (also known as CDO.dll or CDO 1.2.1) is a COM-based (IDispatch only) API based off of Extended MAPI which provides business logic for calendaring objects and address book information. It has been around for quite a while and has been available through Outlook (version with security prompts) and Exchange (no security prompts). CDO 1.21 does NOT ship with Outlook 2007 or Exchange 2007.

 

Points of Interest:

  • CDO 1.21 is built on top of Extended MAPI.
  • CDO 1.21 is not supported in a managed process. So, don't use it in.NET code.
  • CDO 1.21 is not supported in COM+.
  • Extended MAPI and in turn CDO 1.21 has different limitations on Exchange and Outlook
  • CDO 1.21 is installed as a part of Outlook 2007 and prior and also Exchange 2007 and prior.
  • CDO 1.21 is no longer supported for use with Outlook 2010 and later.

Backgrounders:

Overview of CDO
https://msdn.microsoft.com/en-us/library/ms527795(v=exchg.10).aspx

Collaboration Data Objects, version 1.2.1
https://www.microsoft.com/en-us/download/details.aspx?id=3671
Beginning in Exchange Server 2007 and Outlook 2007, CDO 1.2.1 will no longer be provided as a part of the install of the product. As a result, there is functionality missing that many applications depend upon. CDO 1.2.1 is a package providing access to Outlook-compatible objects through a COM-based API.

How Outlook, CDO, MAPI, and Providers Work Together
https://technet.microsoft.com/en-us/library/aa996249.aspx

Collaboration Data Objects (CDO) 1.2.1 is not supported with Outlook 2010 and later versions
https://support.microsoft.com/en-us/kb/2028411

FYI: Why are MAPI and CDO 1.21 not supported in managed (.NET) code?
https://blogs.msdn.com/b/mstehle/archive/2007/10/03/fyi-why-are-mapi-and-cdo-1-21-not-supported-in-managed-net-code.aspx

OUTBOX: Understanding the Exchange store and CDO 1.21
https://blogs.msdn.com/b/mstehle/archive/2006/10/20/outbox-understanding-the-exchange-store-and-cdo-1-21.aspx

 

Also see:

About: Messaging APIs
https://blogs.msdn.com/b/webdav_101/archive/2015/08/07/about-messaging-apis.aspx