Enhancing Security: Microsoft’s New Policy to Restrict Exchange Online Access for Outdated Mobile Devices

Microsoft to Block Mobile Devices Running Outdated Email Software from Accessing Exchange Online

Microsoft recently announced a significant change that will impact mobile devices accessing Exchange Online services. Starting March 1, 2026, devices with Exchange ActiveSync versions below 16.1 will be blocked from connecting to Microsoft’s cloud email service until they are updated.

Exchange ActiveSync (EAS) is a protocol used by Microsoft Exchange to synchronize email, calendar, contacts, and tasks on mobile devices. It is essential for ensuring seamless communication and productivity on the go.

It’s important to note that this change will only affect devices using native email apps and connecting to Exchange Online. On-premises Exchange Server installations will not be impacted. Additionally, devices using Outlook Mobile to access Exchange Online will not be affected, as this app does not rely on the EAS protocol.

The Exchange Team emphasized the need for users and organizations to update their devices and applications to the latest supported versions to avoid any disruptions in service. They provided IT administrators with a PowerShell command to generate a report of devices using older EAS versions within their organizations before the rollout in 2026.

Updates Required for Popular Native Email Applications

Popular native email applications for smartphones, such as those from Google and Samsung, will also require updates to support the newer EAS protocol version. However, Apple’s iOS Mail app already supports ActiveSync 16.1 since iOS 10, ensuring compatibility for iPhones running iOS 10 or later.

The Exchange Team highlighted the extensive collaboration with licensed device and application vendors to facilitate a smooth transition for users. By keeping devices and applications up to date, minimal disruption in service is expected.

Last month, Microsoft addressed an issue that prevented some Microsoft 365 users from connecting to email servers via Exchange ActiveSync with Outlook desktop clients, underscoring the importance of staying current with software updates.