Overview
Microsoft has announced the retirement of Exchange Web Services (EWS) in Exchange Online. EWS remains available for now, but Microsoft has published a phased retirement plan that begins on October 1, 2026 and ends with full shutdown on April 1, 2027.
As part of that plan, Microsoft provides the EWSEnabled setting in Exchange Online to control EWS access at the tenant level. Microsoft documents three possible values for this setting:
$true= EWS enabled$false= EWS disabled$null= default value; currently treated as enabled
Microsoft states that if EWSEnabled remains $null, it will be changed to EWSEnabled = $false as part of the retirement rollout on or after October 1, 2026. However, if you proactively configure an Allow List and set EWSEnabled to $true by the end of August 2026, your tenant will be excluded from that automatic change to EWSEnabled = $false on October 1, 2026.
What this means for Riva customers
Microsoft 365 / Exchange Online
Customers currently using Exchange Web Services (EWS) in Exchange Online should review their usage and begin planning a transition to Microsoft Graph.
Microsoft is retiring EWS in Exchange Online (Microsoft 365).
Organizations that do not take action before October 2026 may be automatically updated from
EWSEnabled = $nulltoEWSEnabled = $false, which will block EWS access.Customers who require additional time beyond October 1, 2026 should follow Microsoft’s Allow List guidance and complete the necessary configuration by the end of August 2026.
EWS in Exchange Online will be fully retired on April 1, 2027.
Exchange On-Premises
The EWS retirement does not apply to on-premises Exchange Server environments.
Customers using Exchange Server on-premises can continue to use EWS without impact from Microsoft’s Exchange Online retirement timeline.
No changes are currently required for EWS usage in on-premises deployments.
How to configure EWSEnabled
Microsoft documents the following Exchange Online PowerShell commands for tenant-wide and mailbox-level control of EWS access:
| Action | Use this command |
|---|---|
| Block the entire organization from using EWS. |
Set-OrganizationConfig -EwsEnabled:$false Important: Disabling EWS in the organization also disables per-user EWS overrides. |
| Allow the entire organization to use EWS. |
Set-OrganizationConfig -EwsEnabled:$true Important: The default value $null is currently treated as EwsEnabled = $true
|
| Block an individual mailbox from using EWS. | Set-CASMailbox -Identity adam@contoso.com -EwsEnabled:$false |
| Allow an individual mailbox to use EWS. | Set-CASMailbox -Identity adam@contoso.com -EwsEnabled:$true |
For more information
Microsoft Exchange Team Blog: Exchange Online EWS, Your Time is Almost Up
Microsoft Learn: Control access to EWS in Exchange
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