New features include:
Calendar and Contact Modern Public Folders are now supported in OWA
Migration for Public Folders to Exchange 2013 including throughput and experience improvements
Smoother support for Exchange Activesync (EAS) clients to O365 when mailboxes are moved in a Hybrid Configuration
The full announcement can be found here, and remember CU8 updates your Active Directory schema.
Oliver Moazzezi - MVP Exchange Server