Feature update: Modern Dynamic Distribution Groups.

March 09, 2022 – Updated:  

Dynamic Distribution Groups (DDGs) are being updated by Microsoft to make them more dependable, predictable, and high-performing. Microsoft is making changes that will increase service dependability, reduce mail delivery latency, and allow you to see who is in a DDG. As part of the launch, this capability will be available to all Exchange Online organisations.

When will this occur: 

Microsoft plans to start spreading this out in early April and finish by mid-April. 

What impact will this have on your company: 

Every time a message is delivered to a Dynamic Distribution Group, the membership list is now computed depending on the filters and constraints you've defined for that group. Due to the complexity of these filters, compiling the recipient list can take a lengthy time, resulting in delayed messages and, in certain cases, dependability issues. Furthermore, because DDGs are only handled after they have been delivered, the sender has no knowledge of the actual recipient list, which may cause compliance issues for our customers.

Changes made recently include: 

• Instead of computing group membership in real time, Microsoft will save each Dynamic Distribution Group's membership list. After that, this list of members will be updated once every 24 hours. 

• Note: After you create or edit the filters of a Dynamic Distribution Group, it may take up to 2 hours for your group to be available to use for the first time. 

Benefits: 

• With this update, you'll be able to confirm a Dynamic Distribution Group's recipient list before sending a message, easing any potential compliance worries. The Get-DynamicDistributionGroupMember cmdlet will let you to see members of Dynamic Distribution Groups. Visit Get-DynamicDistributionGroupMember for more information. Furthermore, Microsoft will deliver messages more rapidly and the service will be more reliable by saving the determined list of members on the Dynamic Distribution Group object.

What you should do to get ready: 

You don't need to do anything because the functionality of Dynamic Distribution Groups hasn't changed. If there are any behavioural changes, you should upgrade your user training and alert your helpdesk. Because the membership list is no longer calculated each time a message is delivered, the recipient list may not always be up to date, even though it is refreshed every 24 hours.