M365 Changelog: Plus addressing: New disable setting and on by default

MC343788 – Plus addressing support in Exchange Online was released in September 2020 as an opt-in feature due to its incompatibility with some preexisting addresses used by customers. New customers had the feature enabled by default and last year Microsoft announced that it would be moving ahead with the plan to turn the feature on for all customers.

That Message center post (MC276028 August ’21) generated a fair amount of feedback from customers who do not intend to allow their users to utilize plus addresses. Considering the feedback, Microsoft announced that it would implement a new setting to allow customers the ability to disable the feature ahead of the change. That setting is now ready for use, and Microsoft is giving customers 30 days to proactively opt out of the feature before it enables plus addressing by default.

Key points:

• Timing: begin mid-April and expect to complete by the late May
• Control: via Exchange Online PowerShell
• Action: make configuration changes to ensure expected experience

How this will affect your organization:

Plus addressing will soon be on by default. If you don’t disable plus addressing, your users will be able to utilize plus addresses after the feature is enabled.

The new setting is DisablePlusAddressInRecipients in the Organization Config. To opt out of plus addressing, run the following command in an Exchange Online PowerShell session:

Set-OrganizationConfig -DisablePlusAddressInRecipients $true

The setting will only start working when Microsoft enables plus addressing for all customers. Microsoft plans to roll out that change after the 30-day notice period expires in mid-April. That change will remove the old AllowPlusAddressInRecipients setting and plus addressing will start working for all customers unless they have set DisablePlusAddressInRecipients to True.

What you need to do to prepare:

To avoid plus addressing becoming available to your users, admins should set the disable setting to True within the 30-day notice period. Customers with addresses containing pluses may also experience disruptions to deliveries. 

Please see Plus Addressing in Exchange Online to learn more.