As we prepare for the final phase of Exchange Web Services retirement, we are refining how EWSAllowedAppIDs setting (which you can use to define your EWS AppID allow list) will be applied. Our goal i...
Published Sep 04, 2026
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If we don't define the EWSAllowedAppIDs manually, when will it be created (so we can check if the entries are correct). Will that be on October 1ste?
Nevermind, I see that the comments on the other article are more active, so asked the question in
- Nino_Bilic
Microsoft
I'm a bit confused; this very blog post talks about how if EWSEnabled = NULL then the change will happen a few days before we switch it to FALSE but if set to TRUE, then we will get to your tenant pretty much immediately, on October 1.
Nino_Bilic I have EWSEnabled = NULL so it means if I do not add any AppIDs to my tenant , Microsoft will add App IDs based on last 60 days usage before making it to False and no impact to the tenant?
- Nino_Bilic
Assume EWSEnabled is NULL.
- Some days before we flip this tenant to FALSE, will add EWSAllowedAppIDs based on EWS use from prior 60 days.
- Now, EWSAllowedAppIDs will be populated but EWSEnalbed is still set to NULL. When EWSEnabled = NULL, the EWSAllowedAppIDs list is ignored. So far, no impact at all.
- Then we come around and turn EWSEnabled = FALSE > this will break EWS for the tenant in about ~1 hour.
- If the tenant admin then needs EWS, all they need to do is set EWSEnabled = TRUE and wait for ~1 hour; that will then use the EWSAllowedAppIDs allow list we populated.
This whole thing about us changing EWSAllowedAppIDs for tenants who are set to NULL is for people who never read anything we posted on this, no docs, no blogs, no MC posts. They are completely unaware and have done nothing. We giving them EWSAllowedAppIDs is just a way for them to be able to set themselves to TRUE once we break them and then within an hour, their EWS should be back up, limited to whatever their EWS usage was within ~60 days before.
Ah my bad, completely missed the "few days" while reading it. I only focused on the section "EWSEnabled = True" and there is it only says Microsoft will populate the list based on the prev 60 days. Sorry for the misunderstanding.
