As customers prepare for the final phase of Exchange Web Services (EWS) retirement in Exchange Online, many are asking the same practical question: how can I prove that EWSAllowedAppIDs is working be...
Updated Oct 14, 2026
Version 5.0
Blog Post
Hi Nino_Bilic Greg Taylor - EXCHANGE
I have done all the changes as suggested (populated the EwsAllowedAppIDs with the test appID, waited for 24hrs and EWSEnabled is set to TRUE and waited for 1 hour) and I tried to run the https://github.com/David-Barrett-MS/PowerShell-EWS-Scripts/blob/master/Legacy/Test-EWSAppAccess.ps1 script. But, I dont see any difference when the EWSEnabled is set to TRUE or if it is null. I also dont see any difference when the EwsAllowedAppIDs is populated with the test app and when it is removed from the EwsAllowedAppIDs list. Everytime I test it, I am getting the "SUCCESS" message and the $LASTEXITCODE is 0.
Should we wait for the October 1st deadline or am I missing something ?
When you removed your test app from the allowed appID, there should be other appID entries left EwsAllowedAppIDs for it to enforce. If not, your test appID will still work.
I did my testing using MS test connectivity and it worked for me as expected >https://testconnectivity.microsoft.com/
- Greg Taylor - EXCHANGE
Microsoft
True with the AppID in the list and Null are going to produce the same result. Even after Oct 1st. True + AppID = allowed. Null means all EWS is allowed.
If you are only using 1 app, then there's your issue - True with an empty list, means all EWS is allowed. Check this post again: Introducing EWSAllowedAppIDs: Preparing for the Final Phase of EWS Retirement | Microsoft Community Hub
Set up a list with 2 app IDs, then remove your test app, and see what happens.
