We're running both exchange 2010 and Exchange 2003. I have an issue where some distribution groups were upgraded to Exchange 2010 (v14.0.100) and the manager of those lists who are on Exchange 2003 can no longer modify members, they get the error:
"Changes to the distribution list membership cannot be saved. You do not have sufficient permission to perform this operation on this object".
We've already implemented the myDistributionGroupsManagement role with success to allow Exchange 2010 users to manage their own list without allowing them to create new ones.
http://blogs.technet.com/b/exchange/archive/2009/11/18/3408844.aspx
Trying to apply the "Default Role Policy Assignement" to the exchange 2003 users returns an error. Is there any way Exchange 2003 users can manage Exchange 2010 Distribution list they owned without being upgraded to Exchange 2010? If not, is there any way to downgrade distribution group to Exchange 2003 once they've been upgraded?