Microsoft has announced the retirement of Exchange Web Services (EWS) for Exchange Online, with service blocking starting October 1, 2026, and full retirement on April 1, 2027. This change affects migrations from Microsoft 365 to Zoho Mail, particularly in-place archive mailbox transfers, which will no longer be supported after blocking begins, according to zoho.com.
The retirement follows a phased approach: Microsoft ceased new feature updates for EWS in 2018 and ended basic authentication support in 2020. Starting October 1, 2026, EWS requests will be blocked in Exchange Online, preventing migration of in-place archive mailboxes to Zoho Mail. However, primary mailboxes, contacts, calendars, and shared mailboxes will still be supported until full retirement in April 2027, when EWS will be completely removed.
This move reflects Microsoft's ongoing shift away from EWS, which has been a core API for Exchange Online integrations. The retirement impacts SaaS providers like Zoho that rely on EWS for mailbox migrations. Organizations using Microsoft 365 must adjust migration strategies, as the discontinuation of EWS will disrupt existing workflows. The timeline aligns with Microsoft's broader security and modernization efforts, emphasizing newer APIs and protocols.
By April 1, 2027, EWS will be fully retired from Exchange Online, ending all dependent applications and services. Organizations planning migrations or integrations with Microsoft 365 should complete necessary transitions before the October 1, 2026 blocking date to avoid service interruptions, zoho.com reported.