{"id":67521,"date":"2026-03-04T13:44:54","date_gmt":"2026-03-04T20:44:54","guid":{"rendered":"https:\/\/cirasync.com\/?p=67521"},"modified":"2026-08-06T17:54:55","modified_gmt":"2026-08-07T00:54:55","slug":"ews-retirement-public-folder-replacement","status":"publish","type":"post","link":"https:\/\/cirasync.com\/de\/public-folder-sync\/ews-retirement-public-folder-replacement\/","title":{"rendered":"Microsoft Is Deprecating Exchange Web Services (EWS): What This Means for Public Folder Integrations"},"content":{"rendered":"

Microsoft has officially announced the retirement of Exchange Web Services (EWS) for Exchange Online, beginning in October of 2026 and ending April 1, 2027. This change has important implications for organizations that rely on third-party applications accessing Public Folder data, especially contacts and calendars.<\/span>\u00a0<\/span><\/p>\n

<\/span>TL;DR – EWS Retirement & Public Folders<\/b><\/span><\/h2>\n

What’s happening:<\/b> Microsoft is retiring Exchange Web Services (EWS) in Exchange Online.<\/span><\/p>\n

Key dates:<\/b><\/p>\n\n\n\n\n\n\n\n\n
Date<\/b><\/td>\nWhat happens<\/b><\/td>\n<\/tr>\n
March 1, 2026<\/span><\/td>\nF1, F3, and Kiosk licenses already blocked from EWS<\/span><\/td>\n<\/tr>\n
End of August 2026<\/span><\/td>\nDeadline to set <\/span>EWSEnabled=True<\/span> + AppID AllowList if you need EWS past October<\/span><\/td>\n<\/tr>\n
September 2026<\/span><\/td>\nMicrosoft pre-populates allow lists based on tenant usage<\/span><\/td>\n<\/tr>\n
October 1, 2026<\/span><\/td>\nEWS starts being disabled tenant-by-tenant<\/span><\/td>\n<\/tr>\n
April 1, 2027<\/span><\/td>\nEWS fully disabled – no exceptions<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Scope:<\/b> Exchange Online only. On-premises Exchange Server is not affected.<\/span><\/p>\n

Public Folder impact:<\/b> Graph will not offer programmatic Public Folder CRUD. EWS-based Public Folder syncs will stop working and cannot simply be re-pointed at Graph.<\/span><\/p>\n

Recommended replacement:<\/b> Shared mailboxes (Graph-supported, modern auth), or a CRM for customer-facing contacts.<\/span><\/p>\n

What to do now:<\/b> Run EWS Usage Reports \u2192 identify Public Folder dependencies \u2192 get vendor Graph plans \u2192 migrate to shared mailboxes with CiraHub keeping data in sync during the move.<\/span><\/p>\n

<\/span>What is Changing?<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

EWS has long been used by third-party applications and custom integrations to access Exchange Online data such as contacts, calendars, mailboxes, and Public Folders. As part of Microsoft\u2019s broader security and modernization initiative, Microsoft begins disabling EWS across Exchange Online tenants on October 1, 2026, with EWS fully disabled on April 1, 2027. The rollout is tenant-by-tenant, controlled by the <\/span>EWSEnabled<\/span> property: any tenant still set to Null on October 1, 2026 is switched to False, which blocks EWS for every application.<\/span><\/span><\/p>\n

Important: This change applies only to Exchange Online. Exchange Server\u00a0on-premises\u00a0is not affected.<\/span>\u00a0<\/span><\/p>\n

<\/span>Impact on Public Folders<\/span><\/b>\u00a0<\/span><\/span><\/h2>\n

One of the most significant consequences of the EWS retirement is its effect on Public Folders. Many third-party tools rely on EWS to read or synchronize Public Folder contacts and calendars. When EWS is disabled:<\/span>\u00a0<\/span><\/p>\n