ReadReceipt on Active Sync Device

Starting from Exchange 2016, now you can disable Read Receipt Feature on Active Sync Device through cmdlet.

Default Output would be:

Get-CASMailbox <User> | fl ActiveSyncSuppressReadReceipt
ActiveSyncSuppressReadReceipt : False

You can set it $Ture and it will change following option in Outlook Web Access as well.

Set-CASMailbox <User> -ActiveSyncSuppressReadReceipt $True