Microsoft began switching off Exchange Web Services (EWS) in Exchange Online on October 1, 2026, and any copier, CRM sync tool, backup product, or custom script your business uses to touch email, calendars, or contacts automatically could be affected. The permanent shutdown, with no exceptions, lands April 1, 2027, so this is the window to find out what you’re running before it breaks on its own.
- Exchange Web Services, the older API many line-of-business tools use to reach a mailbox, started being blocked by default in Exchange Online on October 1, 2026.
- Full, permanent retirement is set for April 1, 2027, and Microsoft has said there will be no extensions.
- Common culprits: copier “scan to email” setups, CRM-to-Outlook sync plugins, email archiving or backup tools, and custom scripts a developer built years ago and nobody has touched since.
- Microsoft Teams, Outlook for Windows, and other first-party Microsoft 365 apps are not affected by this change.
- A short inventory of what actually connects to your mailbox now is cheaper than an emergency fix in early 2027.
What is Exchange Web Services, and why does a small business care?
EWS is a programming interface Microsoft built years ago so outside software could read and write mail, calendar entries, and contacts inside an Exchange mailbox without a person opening Outlook. It became the quiet plumbing behind a lot of ordinary office equipment: a copier that emails scanned invoices straight into an accounting inbox, a CRM that logs sent emails against a client record, a backup tool that archives mail nightly. Most business owners never think about EWS because it was set up once, by a vendor or an IT person, and then forgotten.
What actually happened on October 1, 2026?
Microsoft started a phased shutdown of EWS access in Exchange Online, blocking it by default for any tenant that had not explicitly configured an allow list for approved applications, according to TechRadar Pro. Administrators who needed more time could set an EWSAllowedAppIDs exception and flip EWSEnabled to true before the end of August 2026, but that only buys a few months. As Petri.com reports, Microsoft has confirmed the final cutoff is April 1, 2027, after which EWS stops working in Exchange Online entirely, with no extensions regardless of configuration. Microsoft’s recommended replacement is the newer Microsoft Graph API, though some smaller software vendors have been slow to migrate.
Which of your office tools might be quietly using it?
If your business touches any of the following, it’s worth a check:
Multifunction copiers set up to scan documents directly into a shared mailbox or a specific employee’s inbox. CRM or accounting software with a one-click “log this email” or calendar sync button for Outlook. Third-party email archiving, e-discovery, or backup tools that pull a copy of every message overnight. Any custom integration an outside developer built for you, especially anything older than three or four years, since EWS was the default choice for that kind of work before Microsoft Graph matured.
What should a Boston business do before April 2027?
Start by asking your software vendors whether their product uses EWS and whether a Microsoft Graph-based update is available. Most mainstream CRM and backup vendors have already published guidance; if yours hasn’t, that’s worth raising now rather than in March 2027. If you don’t know what’s connected to your mailbox, a managed IT provider can usually check Exchange admin center logs for EWS activity in well under an hour. This kind of forgotten dependency is exactly the pattern we walked through in our legacy debt audit: old integrations keep working silently until a deadline like this one forces the question.
How does this fit with other Microsoft deadlines this year?
EWS retirement is one of several Microsoft deadlines landing in the same stretch. Windows Server 2016 reaches its own end of support in January 2027, which we covered in detail in our Windows Server 2016 end-of-support guide, and Microsoft 365 is pushing passkeys as the default sign-in method this year as well. None of these deadlines are urgent-sounding on their own, but stacked together they add up to a real amount of IT work between now and spring 2027. Businesses that review all of it at once, rather than reacting to each cutoff separately, tend to spend less on emergency fixes.
Frequently asked questions
What is Exchange Web Services (EWS)?
EWS is an older Microsoft programming interface that lets outside applications read and write email, calendar, and contact data in Exchange. Many copier scan-to-email features, CRM sync tools, and backup products were built on it years ago, often without the business owner knowing.
Does this affect Outlook or Teams directly?
No. Microsoft has said its own apps, including Outlook for Windows and Teams, are not affected and will keep working normally. This retirement targets third-party apps and custom scripts that connect to Exchange Online through the EWS API.
What is the actual deadline?
Microsoft began blocking EWS by default in Exchange Online on October 1, 2026, for tenants that hadn’t configured an exception. The permanent, no-exceptions shutdown is scheduled for April 1, 2027.
What should we do if we don’t know whether we use EWS-dependent tools?
Start with anything that automatically touches your mailbox: scan-to-email on copiers, CRM or accounting software with an Outlook sync button, email archiving or backup tools, and any custom app an outside developer built for you. If you can’t tell, a managed IT provider can check your Exchange admin logs for EWS activity in about fifteen minutes.
If your business runs a copier that scans to email, a CRM synced to Outlook, or any integration nobody remembers setting up, this is the deadline that turns an invisible dependency into a real outage if it’s left unchecked. Boston Managed IT offers a free 15-minute Microsoft 365 review to check your tenant for EWS-dependent apps and flag anything that needs a vendor update before April 2027. Call (617) 322-5155 or visit bostonmit.com/contact to get on the calendar.
— Boston Managed IT
