Exchange Sync BridgeIs Your Software Affected by the EWS Shutdown? A 5-Minute Checklist
On October 1, 2026, Microsoft begins disabling Exchange Web Services (EWS) for Exchange Online tenants — and any third-party software still using it stops syncing without warning. Most firms can't name every application that connects to their mailboxes. This checklist finds them.
Sync Fails Silently, And The Rollout Won't Announce You
Microsoft's EWS retirement is a phased rollout, per Microsoft's EWS retirement FAQ: starting October 1, 2026, tenants are disabled one by one unless an admin explicitly opts to keep EWS. Your tenant could keep working for weeks after a neighboring firm's stops — so "it still works today" tells you nothing about next month.
When EWS is disabled, nothing pops up. The application looks normal; it just quietly stops receiving and sending calendar, contact, or task updates. Email keeps flowing, because Outlook itself doesn't use EWS. The failure only surfaces when someone notices the calendar is stale — and in a law firm, that's an expensive way to find out.
The final cutoff is April 1, 2027, when EWS shuts down for everyone, with no exceptions. The time to inventory your dependencies is before either date, not after.
Five Checks, Five Minutes Each
- List everything that "syncs with Outlook." Walk your software inventory and flag anything that exchanges calendar, contact, task, or email data with Microsoft 365 / Exchange Online. The usual suspects: practice-management sync (Time Matters Exchange Synchronization), voicemail-to-email sync (Cisco Unity Connection), on-premises Dynamics CRM server-side sync, document-management systems, room booking panels, archiving tools, anything that monitors a shared mailbox, and bespoke line-of-business apps. If it "syncs with Exchange" and hasn't been updated in years, assume it's affected until proven otherwise.
- Ask each vendor one question — in writing. "Does your product use Exchange Web Services to connect to Exchange Online, and what is your plan for the October 2026 disablement?" Get the answer in writing, specific to the version you run. Vendors with a real fix will name it (a current version that syncs over Microsoft Graph, as Time Matters 2026 does). A vague answer is an answer.
- Check configuration screens for EWS tells. Open the mail/sync settings of each application on your list. EWS connections typically show a URL ending in "/EWS/Exchange.asmx" (often "https://outlook.office365.com/EWS/Exchange.asmx"), a setting literally labeled "Exchange Web Services" or "EWS," or a service-account username and password. Microsoft Graph connections, by contrast, use OAuth sign-in through Microsoft.
- Check Microsoft Entra ID for EWS permissions. In the Entra admin center, review enterprise applications and app registrations for granted EWS scopes — "full_access_as_app" or delegated "EWS.AccessAsUser.All" are the giveaways. Any app holding those permissions is an EWS client.
- Ask the person who gets called when the calendar is wrong. Every office has one. They know which tools actually touch the calendar and contacts — including the ones that never made it into the official inventory.
Three Paths, In Order Of Effort
For each application the checklist flags, you have the same three options:
- Follow the vendor path, if one exists for your version — a current release that syncs over Microsoft Graph. Confirm it covers your version and your sync usage, in writing, before relying on it. (Note the catch for Time Matters shops: the Graph-based fix is Time Matters 2026, and upgrading requires an active AMP membership.)
- Buy time with Microsoft's allowlist. Tenant admins can explicitly re-enable EWS and allowlist specific applications, extending access until the April 1, 2027 final cutoff. It's a legitimate stopgap — we covered the steps in our post on extending the deadline — but it buys months, not a future.
- Bridge the connection. Exchange Sync Bridge sits between your existing software and Microsoft 365: the software keeps sending EWS requests, the bridge translates them to Microsoft Graph. No vendor update, no upgrade, no retraining — hosted setup typically takes minutes.
Our EWS Retirement Guide goes deeper on each path.
Check Again Next Quarter
A clean inventory is good news, not a permanent one. New tools get adopted, old integrations get re-enabled, and the phased rollout means you won't get a warning shot. Re-run the checklist quarterly until April 2027 — it costs five minutes and it's the only monitoring strategy that works.
Not sure if your software is affected?
Tell us what you run and what it syncs. We'll help you figure out where you stand before either deadline hits.
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