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Exchange Team Blog
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Exchange Online ActiveSync Device Support Update

The_Exchange_Team's avatar
The_Exchange_Team
Platinum Contributor
Dec 15, 2025

We want to inform our users and organizations about an important upcoming change regarding Exchange ActiveSync (EAS) device connectivity to Exchange Online. Starting March 1, 2026, devices running ActiveSync versions lower than 16.1 will no longer be able to connect to our services. EAS 16.1 was released as a part of Exchange Server and Exchange Online in June 2016.

This decision comes after extensive collaboration with multiple licensed device and application vendors to ensure a smooth transition for as many users as possible. If users and organizations keep their devices and applications updated to the latest supported versions, there should be minimal disruption in service. We encourage everyone to verify their devices and applications are up to date before the change takes effect.

An admin can quickly get a report of the devices and apps using versions of ActiveSync below version 16.1 by using PowerShell. Here’s an example:

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

If you have any questions or need assistance with updating your devices, please reach out to your device or application vendor.

Please note that this announcement applies only to Exchange Online (not Exchange Server) and only to mobile devices using native email apps. Apps like iOS Mail app (adopted EAS 16.1 with iOS 10), the Gmail app or the Samsung mail app (both of which are working on updating their apps now, so just keep them up to date and they will start using 16.1 soon) when accessing mailboxes in Exchange Online. Devices that use Outlook Mobile to connect to Exchange Online do not use the EAS protocol and are not impacted.

Thank you for helping us maintain a secure and reliable environment for all users.

The Exchange Team

Updated Dec 16, 2025
Version 2.0
announcements
client access
exchange online
Mobility
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8 Comments

  • MarcinRomanowicz's avatar
    MarcinRomanowicz
    Copper Contributor
    Dec 22, 2025

    Thanks for the update. If anyone needs a more “admin-friendly” reporting script (CSV export + useful device/mailbox fields, easy filtering for ClientVersion < 16.1) please go to https://azure365addict.com/2025/12/22/reporting-legacy-exchange-activesync-clients-after-mc1197103/

  • TriaTechDan's avatar
    TriaTechDan
    Brass Contributor
    Dec 17, 2025

    Get-MobileDevice does not show if devices are active or not and you need to query statistics for each device. The code below gave me actionable output.

     

    $devices = Get-MobileDevice -ResultSize Unlimited | Where-Object {($_.ClientType -eq 'EAS' -or $_.ClientType -match 'ActiveSync') -and $_.ClientVersion -and ([version]$_.ClientVersion -lt [version]'16.1')}
$report = @()
foreach($device in $devices) {
        $stat = Get-MobileDeviceStatistics -Identity $device.id
        $report += [pscustomobject]@{
                DeviceType = $device.DeviceType
                DeviceOS = $device.DeviceOS
                DeviceModel = $device.DeviceModel
                DeviceName = $device.Name
                UserDisplayName = $device.UserDisplayName
                DistinguishedName = $device.DistinguishedName
                Identity = $device.identity
                LastSuccessSync = $stat.LastSuccessSync
        }
}
$report | Out-Gridview

     

  • Ricardo Costa da Silva's avatar
    Ricardo Costa da Silva
    Copper Contributor
    Dec 16, 2025

    One way would be filtering the device ID of one of the "XXXXXX.PROD.OUTLOOK.COM/Microsoft Exchange Hosted Organizat"
    Get-MobileDevice -ResultSize Unlimited | ? {$_.DeviceID -eq "xyz"}
    with the CN in the Distinguished Name or first part of identity you can identify the Mailbox 

  • royytjeeh's avatar
    royytjeeh
    Copper Contributor
    Dec 16, 2025

    When i run the command i get a lot of:
    XXXXXX.PROD.OUTLOOK.COM/Microsoft Exchange Hosted Organizat as a result (besides some real display names). Chopped off and not full. What do i have to do with those? 

    Also the command doesn't return any UPNs.

    Also, would suggest to add the -Resultsize Unlimited parameter because otherwise i didn't get all the results.

    • 4ndr345's avatar
      4ndr345
      Copper Contributor
      Dec 16, 2025

      I think they used AI to generate example code 😄

      This worked for me:

      Get-MobileDevice -ResultSize unlimited | Where-Object {($_.ClientType -eq 'EAS' -or $_.ClientType -match 'ActiveSync') -and ($_.ClientVersion -lt '16.1')} |Select-Object Identity, DeviceId, DeviceModel, ClientVersion