Microsoft are making some changes to calendar AutomateProcessing through PowerShell.
Starting on November 15, 2018, new room and equipment mailboxes (resource mailboxes) that you create in Exchange in Exchange Online PowerShell will have a new default value for the calendar processing property named AutomateProcessing. The new default value will be AutoAccept. The previous default value was AutoUpdate.
You can connect to Exchange Online PowerShell and run the following command to verify the AutomateProcessing property value for all room and equipment mailboxes in your organization:
Get-Mailbox -RecipientTypeDetails @("Equipment","RoomMailbox") -ResultSize unlimited
Impact for users after this change is implemented:
New meeting requests in new room or equipment mailboxes will receive an automatic acceptance message if the resource is free. The resource reservation will be denied if the resource is busy. Meeting request messages are deleted from the Inbox of the room or equipment mailbox after the resource responds to the meeting request. If you don’t want this behavior, change the AutomateProcessing parameter value to AutoUpdate after you create room or equipment mailboxes.
When this change takes effect, anyone who uses the New-Mailbox cmdlet to create room or equipment mailboxes in Exchange Online PowerShell will need to be aware of the new behavior.
If you’re using PowerShell scripts to create room or equipment mailboxes in Exchange Online, and you want to maintain the AutoUpdate value for the AutomateProcessing parameter, you need to modify your scripts to explicitly set the AutoUpdate value.
If you’re already using the AutoAccept value for the AutomateProcessing parameter, or if you aren’t specifying a value and you want new room and equipment mailboxes to have the new AutoAccept default value, you don’t need to do anything.