Batch migration for public folders from Exchange version {0}.{1} (Build {2}.{3}) isn't supported. You must first upgrade ...

Batch migration for public folders from Exchange version {0}.{1} (Build {2}.{3}) isn't supported. You must first upgrade to Exchange 2010 SP3 RU8 or later (http://go.microsoft.com/fwlink/?LinkId=512476). Note that you must upgrade all servers hosting public folder databases and replicas in order for the migration to be successful.