If you're migrating from an earlier version of Exchange, use the information in this article to find out which development technologies are supported in current product versions, and which technology to migrate to.
Determine if your technology is available in current versions
Use the following table to determine whether a development technology is supported in Exchange Online or Exchange 2019. If the technology is not supported, see Choose a development technology to migrate to.
Exchange development technologies and product versions
¹REST API and Graph API require the Cumulative Update 3 for Exchange 2016.
²Only hybrid customers are able to take advantage of the REST APIs for both Office 365 and on-premises mailboxes.
Choose a development technology to migrate to
If the technology your application uses is not supported or deemphasized in Exchange Online or Exchange 2013, use the following table to decide which technology to migrate to.
Recommended technology migration paths
Technology
Supported in Office 365, Exchange Online, and Exchange 2019?
The EWS Managed API and EWS can access the same Exchange store that CDOEX provides. Unlike client applications built by using CDOEX, you can run EWS applications on a local or remote computer.
Exchange Management Shell commands control Exchange servers, storage groups, databases, and users more simply than the corresponding CDOEXM APIs. Plus, you can easily migrate your CDOEXM applications to Exchange Management Shell commands.
The EWS Managed API and EWS provide the same access to the Exchange store that ExOLEDB provides. Unlike client applications built by using ExOLEDB, You can run EWS applications on a local or remote computer.
Although MAPI is currently a supported development technology, you will eventually have to redesign your MAPI applications to use a newer technology.
If your MAPI application is performing simple read, write, and update operations on mail, calendar, or contact objects, and targets Office 365, Exchange 2019² or Exchange 2016¹ ² you can use the Office 365 REST APIs for mail, calendars, and contacts.
If you are targeting Exchange on-premises and you need to access all the properties that MAPI can access, you can use the EWS Managed API or EWS and either schematized properties or extended properties.
NOTE: The ExtendedPropertyDefinition class provides access to MAPI from the EWS Managed API, and the ExtendedFieldURI element provides access to MAPI properties from EWS.
The notifications in EWS provide the same access to the Exchange store that store event sinks provide. You can use Visual Studio tools to streamline the development of store event-aware client applications that use EWS.
Office 365 APIs platform overview, EWS Managed API or EWS
If your WebDAV application is performing simple read, write, and update operations on mail, calendar, or contact objects, and you will be targeting Office 365, Exchange 2019² or Exchange 2016¹ ² you can use the Office 365 REST APIs for mail, calendars, and contacts.
Otherwise, if you are targeting Exchange on-premises and you need access to the same properties in the Exchange store that WebDAV provides, use the EWS Managed API or EWS.