Exchange 2007 includes a new set of Web services that enable developers to interact with Exchange mailboxes and contents by using standard HTTP. Exchange Web Services provides access to the authenticated user's mailbox and the items in the mailbox. Applications can remotely access mail messages, handle meeting requests, look up users in the address book, and determine the availability of other users.

Exchange Web Services enables in-house developers and systems integrators to create applications that enhance the Exchange experience, and facilitate the development of custom systems integration solutions.

Microsoft Exchange Server 2003 developers who currently use WebDAV, Collaboration Data Objects for Exchange 2000 Server (CDOEX), and the Exchange OLE DB (ExOLEDB) provider will find Exchange Web Services to be more robust, easier to use, and better able to handle Exchange-specific item types.

Exchange Web Services includes the following Web services:

• Autodiscover   Provides configuration information for setting up client applications that connect to mailbox servers.
  
• Availability   Provides free/busy data about a user's mailbox. The free/busy data is also used to identify suggested meeting times and provides client Out of Office (OOF) management functionality.
  
• Messaging Records Management    Enables the assignment of Managed E-Mail folders to mailbox users.
  
• Notification   Notifies the client application of events that are associated with a mailbox. The subscription model can be either push- or pull-based.
  
• Synchronization   Provides a one-way synchronized cached copy of a user's folders and items.
  
• Exchange Data Service   Provides the following features:
  
  • Functions to create, update, delete, copy, find, get, and move folders that are associated with a mailbox user, and also the ability to find items that are contained in a folder.
    
  • Access to the Exchange data store. A client application can create, update, delete, copy, get, move, and send items by using the Exchange Data Service Web service.
    
  • Ambiguous name resolution.
    
  • The ability to return the members of distribution list.
    
  • Access to attachments in the Exchange store.
    

For more information about using Exchange Web Services, see the Microsoft Exchange Server 2007 SDK.

The Exchange .NET Framework Extensions provide useful classes and data structures that enable you to access and manipulate the various parts of e-mail messages. The Exchange .NET Framework Extensions includes the following namespaces:

• Microsoft.Exchange.Data.Mime   Enables stream-based and DOM-based access to Multipurpose Internet Mail Extensions (MIME) data, including the ability to filter MIME content.
  
• Microsoft.Exchange.Data.TextConverters   Provides classes and data structures that enable custom filtering of e-mail body content and conversion between several different formats, including HTML, RTF, and plain text.
  
• Microsoft.Exchange.Data.iCalendar and Microsoft.Exchange.Data.Tnef   Provide classes and data structures that let you read and write calendar items for appointments, meetings, and events.
  
• Microsoft.Exchange.Data.Encoders   Provides classes and data structures that let you easily convert the encoding of an e-mail message.
  

For more information about using the Exchange .Net Framework Extensions, see the Microsoft Exchange Server 2007 SDK.

The new Transport APIs in Exchange 2007 enable software developers to create Transport Agents. Transport Agents can be installed and enabled on computers running Exchange 2007 that have the Edge Transport or Hub Transport roles installed. Transport Agents have access to e-mail messages and their contents while the messages move through the transport services. For more information about Transport Agents, see the Microsoft Exchange Server 2007 SDK.

The Exchange Management Shell is a command-line management interface that can be used for server administration in an Exchange 2007 organization. The Exchange Management Shell provides interfaces and objects that are used to develop applications that manage Exchange. For more information about using the Exchange Management Shell, see the Microsoft Exchange Server 2007 SDK.

CDOEX is used to develop messaging applications. CDOEX is used in applications that use messaging to send and process the following:

• E-mail
  
• Calendar and contact information
  
• Access to mailboxes and public folders
  

Note:
CDOEX can only be run on a computer on which Microsoft Exchange is installed.

CDOEX is de-emphasized in Exchange 2007. We recommend you develop new messaging applications using the Exchange Web Services, and migrate existing applications whenever feasible.

CDOEXM was used to develop applications that manage the Exchange 2003 store. CDOEXM is not available in Exchange 2007 and has been replaced by the Exchange Management Shell. Existing applications built using CDOEXM cannot manage Exchange 2007 servers.

CDOWF is used to develop applications that create and manage workflows by using the Exchange store. CDOWF is not available in Exchange 2007. Applications that require workflow automation and orchestration should be implemented using Windows Workflow Foundation. Because maintaining applications that require Exchange workflow functionality require you keep an Exchange 2003 server in your organization, we recommend you consider migrating workflow applications whenever feasible.

MAPI is used to develop applications that access items and folders within public and private stores. MAPI is still supported in Exchange 2007. We recommend you develop new applications using by Exchange Web Services, and migrate existing applications when feasible.

The ExOLEDB provider is used to develop messaging applications. The ExOLEDB provider is used by programmers to access the Exchange store by using OLE DB and ActiveX Data Objects (ADO). Items in the store are accessed by using Structured Query Language (SQL) queries.

Note:
ExOLEDB cannot be used remotely.

ExOLEDB is de-emphasized in Exchange 2007. We recommend that you develop new messaging applications using Exchange Web Services, and migrate existing applications when feasible.

WebDAV is used to develop messaging applications. WebDAV provides access to folders, items, and item properties in the Exchange store. WebDAV can remotely access Exchange. WebDAV is de-emphasized in Exchange 2007. We recommend that you develop new messaging applications using Exchange Web Services, and migrate existing applications when feasible. 

Exchange store event sinks are used to build procedures that respond to events in the Exchange store. The Notification Web service provides an alternative to this technology.