Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html

Published

2026-08-14

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

Cisco copyright; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• Upgrading requires at least 25G of free space on the common partition. in context
• A fresh Disaster Recovery System backup should be taken before upgrading, because an outdated backup can cause data loss or make the system impossible to restore. in context
• Before upgrading, the partition must have no expired certificates, including trust certificates. in context
• Cisco strongly recommends running the upgrade readiness COP file before upgrading to reduce the chance of an upgrade failure. in context
• Custom ringtones and background images are not included in system backups and must be backed up separately before an upgrade. in context
• Cisco's pre-upgrade tasks include recording the registered device count with RTMT so endpoints can be checked after the upgrade. in context
• The pre-upgrade tasks for Release 15 include setting up a Customer Smart Account and creating a Virtual Account for Smart Licensing. in context
• From Release 15SU3, ESXi virtual machines must use a CPU mode that supports AVX. Where VMware EVC is configured, its settings must be checked. in context
• After regenerating expired identity certificates during pre-upgrade cleanup, take a backup so the new certificates are preserved. in context
• The common partition needs at least 25 GB free before upgrading. Cisco warns that an upgrade can still fail with an insufficient-space error even with 25 GB free. in context
• DRS backups do not include custom TFTP content: Ringlist.xml, List.xml, custom ringtones and background images. Back these up separately before upgrading. in context
• Before upgrading, check database health with a CURT Database Status Report and with utils dbreplication status and utils dbreplication runtimestate. The replication setup value should be 2 for every node. in context
• The upgrade can overwrite IM and Presence enterprise parameters with Unified CM values when the two differ. Screenshot both sets beforehand. in context
• Installing the Free Common Space COP file makes the inactive partition unusable, so you can no longer switch back to the inactive (previous) version. in context
• Take a fresh DRS backup just before the upgrade. Cisco cautions that an outdated backup can lose data or leave the system unrestorable. in context
• Before upgrading, disable High Availability on each Presence Redundancy Group and stop the Cisco Sync Agent on IM and Presence. Re-enable both afterward. in context
• Cisco lists upgrading IP phone firmware through the TFTP server as an optional task before the Unified CM upgrade. in context
• The pre-upgrade readiness COP checks for common problems such as low disk space, service status and expiring certificates. Cisco says to re-run it until it reports no errors. in context
• Before upgrading, record the registered device counts from RTMT (phones, gateways and media resources) and the IM and Presence assigned-user counts, then compare them after the upgrade. in context
• The upgrade changes the TFTP Maximum Serving Count service parameter. Record its value beforehand and reset it after the upgrade. in context
• For large clusters, raise the database replication timeout on the publisher with utils dbreplication setrepltimeout before upgrading, then restore the 300-second default afterward. in context
• Add a serial port to each VM before upgrading so install logs can be dumped if the upgrade fails. Remove it afterward because it affects VM performance. in context
• If space is short, Cisco suggests temporarily lowering the RTMT log-partition low and high watermarks from their defaults (80 and 85) to 30 and 40, then restoring them after the upgrade. in context

Cite this source record

APA

WarmTransfer. (2026, August 14). Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process). WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-cucm-upgrade-15-pre-upgrade

BibTeX

@misc{warmtransfer-cisco-cucm-upgrade-15-pre-upgrade,
  title  = {Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-cucm-upgrade-15-pre-upgrade},
  note   = {Cisco Systems, accessed 2026-09-24}
}