EWS Migration
Exchange Web Services (EWS) is a technology specifically developed for accessing Exchange data. The API provides access to data from Microsoft Exchange Server and Exchange Online, including emails and mailboxes. EWS has served as a central interface for third-party solutions such as archiving systems.
Microsoft is Discontinuing Exchange Web Services (EWS) for Microsoft 365
Microsoft has announced that it will disable Exchange Web Services (EWS) access for Exchange Online starting October 1, 2026. EWS will be completely shut down by April 2027. This decision affects all organizations using EWS with Exchange Online (Microsoft 365). After the shutdown, access to some resources will only be possible through the Graph API, while other resources currently have no Graph API equivalent. These resources will no longer be accessible via third-party solutions.
Microsoft will begin to configure and potentially restrict access to EWS based on usage from August 2026. Administrators can manage these settings themselves.
For customers using Exchange Online Kiosk, Microsoft Office 365, and Office 365 F1/F3, Microsoft will disable EWS access starting June 2026.
What Changes Will Occur for MailStore Server and MailStore SPE?
The discontinuation of EWS by Microsoft will require changes in MailStore Server and MailStore SPE depending on the archiving strategy. The archiving methods used in MailStore Server and MailStore SPE, which previously relied on EWS, may not be able to connect after October 1 and may encounter errors.
Which Protocols Does MailStore Use?
Up to version 25.4, MailStore specifically created Microsoft 365 archiving and export profiles that used EWS. From version 26.1 onwards, new archiving profiles for normal mailboxes use the Graph API. New archiving profiles for archive mailboxes and public folders continue to use EWS, as they cannot be accessed via the Graph API. From version 26.2 onwards, new export profiles use the IMAP protocol; because it is not possible to transfer complete emails from Microsoft 365 mailboxes via the Graph API.
How Can MailStore Support You During the Transition?
According to our instructions, make sure you have completed the application registration in Entra ID. Specifically, the Mail.ReadWrite and IMAP.AccessAsApp permissions are now required.
The summary of archiving profiles includes the protocol used. Microsoft 365 Journal archiving profiles generally do not use EWS and are therefore unaffected.
If you have configured convertible Microsoft 365 profiles, the following message will appear in the dashboard:
Click on this message to open the Microsoft 365 Profile Conversion Tool. Use this tool to test and perform conversions.
When Should the Settings Be Adjusted?
June 2026
If you are a customer of Exchange Online Kiosk, Microsoft Office 365, or Office 365 F1/F3, all profiles must be migrated to Graph API and IMAP.
Archiving Exchange Online archive mailboxes and Exchange Online Public Folders will no longer be possible.
October 2026
If EWS access in Microsoft 365 is configured appropriately, EWS profiles will continue to work after October 2026.
April 2027
EWS profiles will no longer work after April 2027. Archiving normal mailboxes via Graph API and transferring to Microsoft 365 via IMAP will continue to work. Archiving Exchange Online archive mailboxes and Exchange Online Public Folders will no longer be possible. Microsoft has given hints about a future solution, but no concrete plan has been published yet. Microsoft recommends migrating public folders to Microsoft 365 Groups.