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Microsoft details how to re-enable Exchange Online EWS for apps broken by the default block

1 fonte(s) · 1 atualização(ões) · publicado 22/10/2026 12:49 · coletado há 4 horas

Microsoft says Exchange Online administrators can temporarily re-enable the retired Exchange Web Services (EWS) API to restore apps that stopped working after the default block began on October 1, 2026. EWS is used by Outlook desktop add-ins, older Outlook for Windows versions, Apple Mail/Calendar on macOS and other apps. When EWS is disabled, these apps show errors, from messages that the EWS protocol is unavailable to repeated credential prompts. Re-enabling is only a stopgap, because EWS is scheduled for final shutdown on April 1, 2027. The retirement affects only Microsoft 365 and Exchange Online, and on-premises Exchange Server is unaffected.

Detalhes técnicos

  • Microsoft announced in February that EWS would be blocked by default from October 1, 2026, with an app allowlist letting admins keep temporary access until April 1, 2027.
  • Microsoft's earlier timeline: a 2018 warning that EWS would get no more functionality updates, a September 2023 announcement of the October 2026 shutdown start, and the 2021 deprecation of the 25 least-used EWS APIs, removed in March 2022 for security reasons.
  • Microsoft says the Microsoft Graph API has near-complete feature parity with EWS for most scenarios.

Remediação

  • In the Microsoft 365 admin center, open the Baseline Security Mode page and uncheck "Block your entire organization from using EWS".
  • Alternatively, run Set-OrganizationConfig -EWSEnabled $true in Exchange Online PowerShell. The change should take effect within 4 hours.
  • Re-enabling will stop working in April 2027. The long-term fix is to update applications to versions that do not use EWS, either by getting them from the vendor or by changing the code of in-house apps.
  • Developers should migrate EWS-based apps to Microsoft Graph before the shutdown.

Linha do tempo

  1. bleepingcomputer.com ↗ · pub. 22/10/2026 12:49 · coletado 22/10 13:00 primeiro registro

    Microsoft details how to re-enable Exchange Online EWS for apps broken by the default block

    ler a análise desta fonte

    Microsoft says Exchange Online administrators can temporarily re-enable the retired Exchange Web Services (EWS) API to restore apps that stopped working after the default block began on October 1, 2026. EWS is used by Outlook desktop add-ins, older Outlook for Windows versions, Apple Mail/Calendar on macOS and other apps. When EWS is disabled, these apps show errors, from messages that the EWS protocol is unavailable to repeated credential prompts. Re-enabling is only a stopgap, because EWS is scheduled for final shutdown on April 1, 2027. The retirement affects only Microsoft 365 and Exchange Online, and on-premises Exchange Server is unaffected.

    Technical Details

    • Microsoft announced in February that EWS would be blocked by default from October 1, 2026, with an app allowlist letting admins keep temporary access until April 1, 2027.
    • Microsoft's earlier timeline: a 2018 warning that EWS would get no more functionality updates, a September 2023 announcement of the October 2026 shutdown start, and the 2021 deprecation of the 25 least-used EWS APIs, removed in March 2022 for security reasons.
    • Microsoft says the Microsoft Graph API has near-complete feature parity with EWS for most scenarios.

    Remediation

    • In the Microsoft 365 admin center, open the Baseline Security Mode page and uncheck "Block your entire organization from using EWS".
    • Alternatively, run Set-OrganizationConfig -EWSEnabled $true in Exchange Online PowerShell. The change should take effect within 4 hours.
    • Re-enabling will stop working in April 2027. The long-term fix is to update applications to versions that do not use EWS, either by getting them from the vendor or by changing the code of in-house apps.
    • Developers should migrate EWS-based apps to Microsoft Graph before the shutdown.