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
Nino_Bilic
Microsoft
Microsoft- Yes you can do those things in September; we wanted to set a date for folks to get it done before enforcements start in October but there is nothing magical about August as far as this goes.
- If EWSEnabled = True and AppID Allow List is empty, then all EWS apps will be allowed, yes. If AppID allow list is populated then only applications on the list will be allowed (plus cross-tenant free/busy lookups). Other apps (not in the list) woiuld be blocked.
- Yes you should wait for full 24 hours. Yes, it COULD happen faster for you. But if you want this to be predictable, 24 hours.
- Unclear what you mean about question on how to test EWSAllowedAppIDs; this article is about how to test this... right?
- Well... if you see applications in EWS usage reporting, that confirms EWS use, does it not? :) I do not fully understand this question. Bottom line is - unless it is on the AppID Allow List and the Allow List exists, it will be blocked.
Greg Taylor - EXCHANGEMicrosoft
MicrosoftOne thing on this : "If EWSEnabled = True and AppID Allow List is empty, then all EWS apps will be allowed, yes. "
This is only true until Oct 1st. Oct 1st is a hard deadline whereby if the AppID Allow List is empty or missing - EWS will be blocked. Configuring the Allow List is important.
Thanks Nino_Bilic and Greg Taylor - EXCHANGE Appreciate your response.
