Requirements and Limitations
The following sections provide information about the requirements that your system must meet, and limitations that apply when you install or upgrade Unified Communications Manager or Instant Messaging and Presence serivce.
Do not modify any of the Instant Messaging and Presence Service server entries on the Application Server or Server configuration pages of the Cisco Unified CM Administration interface. The Instant Messaging and Presence Service upgrade process automatically updates these entries on the Unified Communications Manager cluster during the final stages (switch version) of the upgrade process.
For upgrades from Release 8.x or 9.x to Release 10.x or later, any manual modification of these entries during the upgrade process will result in data migration failures between Instant Messaging and Presence Service and Unified Communications Manager. If such failures occur, you must restart the entire upgrade process for both Unified Communications Manager and Instant Messaging and Presence Service clusters.