Hi,
Please try the steps below:
1.Get the mailbox which are limited to user type and not hidden from the address book:
$Mailboxes = Get-Mailbox -RecipientTypeDetails UserMailbox -ResultSize Unlimited -Filter {HiddenFromAddressListsEnabled -eq $false}
2.Return all the mobile devices which are associated with the mailboxes:
$Devices = $Mailboxes | %{ Get-ActiveSyncDeviceStatistics -Mailbox $_.Identity}
3.Get the information we are interested in :
$Devices | Group-Object | select Name, DeviceType, Last*, First*, SyncStateUpgradeTime
Regards,
Rebecca