Comparison between CCM 4.x and CCM 6.1
CUCM 6.x version runs on linux appliance platform. It has a backup partition for quick roll back of upgrades.
Some of the new features in CUCM 6.X are listed here:
1. Database resiliency. User-facing features are still changeable in the event of the Publisher going down
(like Call Forward All).
2. Increased ease in upgrades and patches.
3. Mobility incorporated into 6.
4. Single-button barge
5. Join Across Lines
6. Ease of major upgrades in the future.
7. Read-only synchronization with AD (now making it more tempting to get the LDAP directory from AD).
8. Busy Lamp Field/Speed Dial.
9. Presence server.