When considering software upgrades, also consult http://www.cisco.com/go/psirt
and any subsequent advisories to determine exposure and a complete upgrade solution. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Release" column of the table.
|Cisco Unified Communication Manager Version
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.