Exchange Online to Drop Support for Legacy Mobile Email Apps Starting March 2026

Microsoft has announced that it will block mobile devices running outdated email software from accessing Exchange Online starting March 1, 2026. The change targets older implementations of Exchange ActiveSync and aims to reduce security risks tied to legacy protocols.

What exactly is changing with Exchange Online

Microsoft will prevent devices using Exchange ActiveSync (EAS) versions older than 16.1 from connecting to Exchange Online. EAS 16.1 launched in June 2016 and no longer meets modern security expectations.

Only native email apps that rely on legacy EAS versions face impact. Outlook Mobile users will not see any disruption because the app does not use the EAS protocol.

Who is affected and who is not

Mobile devices using built-in or older email clients that still depend on pre-16.1 EAS versions may lose access after the cutoff date. Older Android mail apps fall into this category unless vendors update them in time.

Apple’s iOS Mail app already supports EAS 16.1 on iOS 10 and newer, so most iPhone users should continue working without issues. Google and Samsung have confirmed they are updating their native email apps to support the newer protocol.

On-premises Exchange Server installations are not affected by this change.

Tools for IT administrators

Microsoft shared a PowerShell command that allows administrators to identify devices still connecting with older EAS versions. This gives organizations time to audit users, notify employees, and enforce upgrades before March 2026.

Get-MobileDevice | Where-Object {($_.ClientType -eq 'EAS' -or $_.ClientType -match 'ActiveSync') -and $_.ClientVersion -and ([version]$_.ClientVersion -lt [version]'16.1')} | Sort-Object UserDisplayName | Select-Object UserDisplayName, UserPrincipalName, DeviceId, DeviceModel

Many organizations already block legacy EAS clients and require Outlook Mobile for improved security controls and device management. Because of that, the upcoming block does not come as a surprise for enterprise IT teams.

Why Microsoft is enforcing this now

Legacy EAS versions lack modern security protections and management features. By enforcing EAS 16.1 or newer, Microsoft reduces exposure to vulnerabilities and aligns Exchange Online with current security standards.

The company continues to push users toward supported clients and actively maintained apps, especially as cloud security threats keep increasing. In other news, Microsoft has added DeepSeek-V3.2 models to Azure, so if you use this platform, be sure to give them a try.

Via Bleeping Computer