While Office 365 still offers public folders, it is moving it’s users to use more Office 365 Groups for collaboration and simplicity. With Office 365 Group, you will offer a central management for all the application surrounding the group. When creating an Office 365 Group, apart from creating an actual group with an email address, shared mailbox, shared calendar, SharePoint Online site and Planner dedicated to that group, you can also create Teams, Stream, Notebooks and other applications easily and associated to the same group. Like this anyone who is part of that group, will automatically have access to any resource which is created with the group.

If you are coming from an on-premises migration, you will have several distribution groups. Now, you can delete and re-create them as Office 365 Groups, but Microsoft offers a way for you to upgrade your existing Distribution Groups to Office 365 Groups and retain all the information like email address and members.

How to Upgrade Distribution Group

To upgrade a distribution group, there are two ways. You can upgrade using the Exchange Admin Center in your Office 365 tenant or by connecting to your tenant using the Exchange Online Management Shell using PowerShell.

Upgrade Distribution Group Using Exchange Admin Center

When migrating using the portal, you will need to open the Exchange Admin Center and click on the Groups under Recipients. Click on Distribution list, select the group to upgrade and click on the more settings. Click on Upgrade distribution group.

Microsoft 365 Groups

Once you click on the upgrade, you will get the message that the upgrade is in progress.

distribution Groups

Upgrade Distribution Group Using Exchange Online Management Shell

To upgrade a distribution group to Office 365 Group using the Exchange Online PowerShell, you will need to use the Upgrade-DistribtionGroup command as below

Upgrade-DistributionGroup -DlIdentities <group email address>

Upgrade Distribution Group

Although most of the time this should work like a charm, you might have issues when migrating them. There could be reasons and culprits which could block the migration process where some of which can be the following,

  • Case sensitivity in the email address due to policies
  • The distribution group is not of the correct type
  • Having more than 100 owners
  • Having no owners

All these can factor in the issue on why the upgrade is not possible. To see the full list of requirements when upgrading distribution groups to Office 365 along with the list of which distribution lists can’t be upgraded.


How to change the Groups to Office 365

There are two ways to change the groups to be Office 365 friendly. You can go one by one and change the culprits from the Exchange Admin Center interface. Else, if you have several groups which have the same issue, you might better make sure of the Exchange Online PowerShell to make sure that you can automate the process and not going one by one to make a repetitive change. To give an example which is the most common issue, which is the case sensitivity, one can use the following procedure.

First you would need to create the correct email address as the primary email address as below

Set-DistributionGroup <group name> -PrimarySmtpAddress <new email address>

Then we need to remove the culprit email address as below

Set-DistributionGroup <group name> -EmailAddresses @{remove=”<incorrect email address>”}

You can do the above in a loop to change all the groups at once. Once executed, you can then confirm that the change has been affected by running the below

Get-DistributionGroup <group name> |fl PrimarySmtpAddress,EmailAddresses

Migrating to Office 365 Groups is a great way to move away from Public Folders and using the new modern workplace. With Office 365 Groups you can much more than just a group as everything revolves around it. It’s easy to implement and use while it increases productivity and collaboration. The only issue is the migrations process which would take some considerate amount of time and effort due that there is no straight forward migration process from on-premises public folders to Office 365.


Thankfully, you can use third-party EDB to PST Conversion applications like Stellar Converter for EDB, which can help our process to be smoother and reliable without any additional resources or administrative effort. Stellar Converter for EDB, can open multiple EDB files at once from any version of Exchange Server. Once the EDB file/s are scanned, you will be presented with a great familiar interface which you can browse all your datastores, being mailboxes, shared mailboxes, and public folders. Here you can export granularly or with a search filter to PST and other formats. You can also search in-line and in real-time on your databases. You can export directly to a live Exchange Server database of any version and to an Office 365 tenant. For the migration of public folder into Office 365 groups, the application can be used to import into the shared mailbox of the group itself. Having said that, you can prioritize the export with VIP users, parallel migration to improve performance and continuation in case the migration is interrupted with the facility to auto match the users in the Exchange Server or Exchange Online.