When migrating to Exchange 2010 from Exchange 2003, you may be carrying over several mail-enabled non-universal groups. These groups will still function, but the administration of these objects within the Exchange tools will be limited. In addition, several distribution group features provided by Exchange 2010 will not be enabled for a group until it has been upgraded. This recipe covers the process of converting and upgrading these groups within the Exchange Management Shell.
To convert all of your non-universal distribution groups to universal, use the following one-liner:
Get-DistributionGroup -ResultSize Unlimited ` -RecipientTypeDetails MailNonUniversalGroup | Set-Group -Universal
Once all of your distribution groups have been converted to universal, you can upgrade them using the following command:
Get-DistributionGroup –ResultSize Unlimited | Set-DistributionGroup –ForceUpgrade