Microsoft has confirmed that Exchange Web Services (EWS) for Exchange Online / Microsoft 365 will be fully shut down on April 1, 2027, ending nearly 20 years of API support.
🗓 Timeline
- Oct 1, 2026 – EWS blocked by default in Exchange Online
- Admins can temporarily allowlist apps
- Apr 1, 2027 – EWS fully disabled (no exceptions)
📌 Important scope clarification
- ❌ Affects Exchange Online / Microsoft 365 only
- ✅ On-prem Exchange Server will continue to support EWS
- Hybrid environments must carefully evaluate mailbox location
🧭 What Microsoft recommends
- Developers should migrate to the Microsoft Graph API, which now offers near-feature parity
- Hybrid customers must use Exchange Server SE to support Graph access to cloud mailboxes
💬 Microsoft:
“EWS was built nearly 20 years ago and no longer aligns with today’s security, scale, or reliability requirements.”
This retirement follows years of gradual depreciation:
- Functionality freeze since 2018
- Least-used APIs removed in 2022
- Formal retirement plan announced in 2023
⏳ Bottom line:
If you still rely on EWS in Microsoft 365, migration planning is no longer optional.
