Retirement of Exchange Web Services in Exchange Online

Those same gaps have been repeatedly brought by the community/ISVs since the original "deprecation" notice, yet 5 years later we've seen zero movement on that front. Are you actually going to address them?

Few years ago, when we investigated replacing our EWS solution with Graph API, I became aware of the following issues. Some are based on our own research, some are from other comments, so take the list with a grain of salt.

I would like to tout the same horn as VasilMichev..   we have been pointing out deficiencies in the "replacements" for EWS for years...  without any movement. How is this time going to be different? How can you announce a retirement without even having the plans to provide parity? This is, as we like to say, "suboptimal".

I echo the concerns raised by @Vasil Michev and MichelZCF about the feature gaps between EWS and Microsoft Graph. These gaps have been pointed out by the community for years, yet we haven't seen considerable progress in addressing them. Announcing the retirement of EWS without a clear roadmap to achieve feature parity seems premature and, frankly, very concerning.

My question to Microsoft is: Will customers and partners end up with a premium (paid per API call) Graph to achieve similar functionality to EWS?

While we're at it, I want to echo what Vasil, Peter, and Michel have said: we have been waiting for years to get functionality parity in Graph as an EWS replacement. Removing EWS capability is going to cause major problems for our customers-- in my case, I don't want to have to tell them "oh, sorry, we can't back up public folders any more" (to cherry-pick one example) but killing EWS without replacing its functionality is going to lead to that.

Last time we talked about this, we communicated no more features were going to be added to EWS (instead, any new functionality was going to be added to Microsoft Graph). This time, answering your question VasilMichev et al., we spent a couple of semesters analyzing EWS telemetry and meeting third-party developers to not only identify gaps and understand business cases behind the feedback received by the community/ISVs, but also to prioritize the effort to close these gaps and plan their implementation with the engineering teams.

So yes, we are already addressing many of these. We will update this same thread when major features hit either beta or v1 endpoints.

MichelZCF 

For completion's sake and to prevent any confusion for others reading this; That sentence got replaced with;

"We previously announced that we planned to prevent registration of new apps in Azure with EWS permissions, but based on your feedback we have decided to postpone this plan for the time being."

It's a very early decision for Ews to retire.

Is there a report that will show us who is using EWS so we send communication to them?

A few points around the topics mentioned above:

• We are working to provide detailed communication through Message Center to specific tenants where we observe EWS activity. This is WIP, for now all tenants with Exchange online licenses will get a broader announcement with the same wording of this blog. EricToetz 
• Now that basic auth was deprecated and all apps should be using OAuth to access EWS, I'd say the easiest way to identify such apps would be to check Azure AD admin center for registered app with either EWS.AccessAsUser.All or full_access_as_app permissions listed, it'd probably make sense to also check Azure AD sign-in logs to validate those apps are still active. I'm positive this should be achievable through PowerShell; I will ask someone from the team to take a look at it and get back to us. Thanks for the valuable feedback jrbarker. 
  
  
• Thanks for the comprehensive list lukaaash. Some of the gaps you listed are part of our backlog and some others are probably no longer valid: as the MIME case clarified by RobertSparnaaij, access to distribution lists or support for organizational contacts.
  Regarding OnPrem, EWS continue to be available for it and there is no plan to enable its access through Microsoft Graph. Similar to this, there is no plan to implement streaming notifications (you might want to take a look at the use of delta queries to track changes. Also, Event Grid and Event Hubs are now offered to deliver notifications besides webhooks).