Quest On Demand Migration: ready for the EWS shutdown?

Short answer: Quest On Demand Migration still uses EWS for mail migration and is moving to Graph in stages. Keep its app IDs on the allow list while migrations run and follow Quest KB 4380720 for the new permissions.

✖ Still needs EWS · vendor statements checked 26 Oct 2026

Deadline: Exchange Online blocks EWS by default from October 2026 (tenants are switched to EwsEnabled False, rollout to late April 2027) and turns it off for good on 1 April 2027, with no exceptions. Exchange Server on-premises is not affected.

Status

Still EWS, staged Graph move (Quest KB 4380720). App IDs as listed by lazyadmin.nl from Quest's documentation.

App IDs in the EWS usage report:

What to do

  1. Check which of the three IDs appear in your EWS usage report.
  2. Add those to the allow list for the migration project.
  3. Grant the new email-migration permissions from KB 4380720 when Quest switches your project to Graph.

More than one app? Run the free read-only script: it names every app still calling EWS in your tenant.

Allow-list it safely

Setting EwsAllowedAppIDs replaces the whole list, so adding one ID on its own removes every other app. Read the current list first, then write the merged list:

Get-OrganizationConfig -RetrieveEwsOperationAccessPolicy | Format-List EwsEnabled,EwsAllowedAppIDs
Set-OrganizationConfig -EwsEnabled $true -EwsAllowedAppIDs "<current IDs>,<new ID>"

Changes to the list take up to 24 hours. A blocked call returns HTTP 403 with the header X-EWS-Policy-Reason. The free script prints the merged command for every app in use (it never runs it).

Sources

MSP or IT partner? The M365 Readiness Pack runs this EWS check, the SMTP AUTH check and SPF/DKIM/DMARC for every domain once per client tenant, and writes a client-ready report with your logo, next steps and an email to send the client. Read-only, works with GDAP.

See the pack (from $49)
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