Hi Martin,

Just to build on the great info from Eugene;

Cisco Unified Communications Manager 6.0 feature enhancements:

•AAC/iLBC Voice Codec Support

•Advanced Ad Hoc Conference

•Audible Message Waiting Indicator

•Barge Enhancements

•Call Diagnostics and Voice Quality Metrics

•Call Forward Enhancements

•Call Forward All Calling Search Space Backward Compatibility

•Call Forward Overriding

•Call Pickup Notification

•Cisco Messaging Interface Enhancements

•Cisco Unified Communications Manager T1 CAS Hookflash Transfer Support

•Connected Number Display

•Credential Policy and User Authentication

•CTI Enhancements

•Device Mobility

•Directed Call Park

•Do Not Disturb

•Hold Reversion

•Intercom

•Licensing Enhancements

•Log Out of Hunt Groups

•Overlap Sending and Receiving for H.323 Gateways

•MGCP T.38 Enhancements

•Privacy on Hold

•Programmable Line Keys

•SCCP Optimization

•SDL Traces

•SIP Endpoints Support

•SIP Third-Party Phones Enhancements

•SIP Trunk Enhancements

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/6_0_1/601cmrn.html#wp44812

Hope this helps!

Rob