October 2026
EWS retirement begins
Microsoft starts removing EWS endpoints across Exchange Online tenants. Any application using EWS Managed API begins to fail.
Hard deadline: October 2026
EWS Managed API alternative
Microsoft is retiring Exchange Web Services. If your organization still runs EWS Managed API code for contact sync, CYNC is the drop-in, Graph-native replacement without the migration project.
The EWS retirement timeline
Now → Oct 2026
Migration window
Every internal tool using Microsoft.Exchange.WebServices needs to be ported to Microsoft Graph or replaced.
Post-retirement
Hard failure
EWS-based contact sync stops working. Mailboxes no longer receive updates. Caller ID on mobile devices goes stale.
Why teams replace instead of port
Hard deadline
Unlike past Microsoft deprecations, EWS retirement has a published date. There's no extension path. Your code stops working.
Engineering cost
Porting an EWS Managed API codebase to Microsoft Graph is non-trivial. The auth model, protocol, batch semantics, and throttling rules all differ.
Opportunity cost
The engineering hours spent rewriting an internal sync tool are hours not spent on differentiated work. Buying CYNC frees that team up.
Reliability
Internal EWS tools rarely have full throttling, retry, and observability built in. CYNC delivers all of it as a product, validated across thousands of tenants.
CYNC is 100% Microsoft Graph
Zero EWS dependency. CYNC was designed Graph-first from day one. There is no port roadmap, no protocol risk, no October 2026 rewrite hanging over your team.
See how CYNC uses Microsoft GraphEWS Managed API FAQ
What is the EWS Managed API?
Microsoft.Exchange.WebServices.Data is the .NET client library Microsoft shipped to consume Exchange Web Services. It's been the default approach for Exchange automation in C# / PowerShell scripts for over a decade. With EWS retiring in October 2026, the API is effectively obsolete.
Is the EWS Managed API really deprecated?
Microsoft has formally announced EWS retirement for many scenarios in October 2026 and recommends Microsoft Graph as the replacement. The EWS Managed API NuGet package has not received feature updates and is on the deprecation track.
Can I just port my EWS code to Graph?
You can, but it's a real project. Authentication moves from basic auth or OAuth-with-EWS-scopes to MSAL with Graph scopes. Endpoints change shape (REST/JSON vs SOAP/XML). Batch request semantics differ. Throttling rules differ. Error handling differs. For most teams, replacing the script with a managed product is faster.
How does CYNC fit?
If your EWS Managed API code reads users from Entra ID and writes them as contacts to Exchange Online mailboxes, CYNC replaces the entire codebase. Retire your EWS service and run CYNC instead. No port, no maintenance, fully Graph-native.
What if my EWS code does more than contact sync?
Then you have a partial replacement opportunity. Use CYNC for the contact sync portion (offload the deprecation risk on that workload) and continue porting your remaining EWS workloads to Graph at your own pace.
How fast can I cut over?
Install CYNC in 15 minutes, register an Entra ID app, and run a pilot sync to a small mailbox group within an hour. Once validated against your existing EWS output, retire the legacy script.
Retire EWS before EWS retires you.
Get 10 users free per tenant. Install CYNC and run shadow mode against your existing EWS sync.