Overview
- Devices using ActiveSync versions below 16.1 will be unable to connect starting March 1, 2026.
- The enforcement targets native mobile mail clients on the cloud service, not on‑premises Exchange Server deployments.
- Outlook Mobile is unaffected because it does not rely on the ActiveSync protocol.
- Administrators can inventory at‑risk devices with the provided Get‑MobileDevice PowerShell query.
- iOS Mail already uses 16.1, while Google Gmail and Samsung mail apps are rolling out updates.