How EWS retirement affects Sent Items Update (SIU) in CodeTwo Email Signatures 365

Problem:

Microsoft plans to retire Exchange Web Services (EWS) for Exchange Online (Microsoft 365 only) in October 2026. If you use the Sent Items Update (SIU) feature in CodeTwo Email Signatures 365, you might have received the following notification in your Microsoft 365 tenant’s Message center:

Action Required: Update active Exchange Web Services Applications

(...)

In October 2026 we will begin disabling EWS on all M365 tenants worldwide. EWS Applications that have not been migrated will stop functioning.

The following applications on your tenant use EWS:

Entra Application ID

3153c72b-35a8-465b-84d8-dfb56651836a

You want to know if there is anything you need to do to continue using SIU.

Solution:

The AppID mentioned in the message refers to the CodeTwo Email Signatures 365 - Sent Items Update app in your Entra ID. This is the old version of the SIU cloud service that uses EWS to update emails in the Sent Items folder with the signature that was added in the cloud (after the email was sent). This service does not affect the process of adding CodeTwo signatures to outgoing emails.

We’ve already released a new SIU version that uses Graph API instead of EWS. You need to switch to the new version if you want to continue using SIU. See this guide for detailed instructions