A version-switch rollback exists only while the previous release still sits intact on the inactive partition. After a migration, a fresh install with data import, or a Free Common Space COP install, the only documented way back is reinstalling the source release and restoring a same-version DRS backup.

inferred · Checked 2026-09-25

Vendor

Cisco

Product

Unified Communications Manager

Subsystem

rollback

Deployment

on-premises

Region

not restricted

Release range

Release 15 and SUs as of 2026-09-25

Status

inferred

Checked

2026-09-25

Sources

• Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade — Cisco Systems · tier 2 current vendor documentation · Planning the Upgrade > Version Switching; combined with Pre-Upgrade Tasks > Maximize Usable Disk Space and Restore the System > Restore Prerequisites

Cite this note

APA

WarmTransfer. (2026, September 25). Planning a Unified CM upgrade: source note cucm-upgrade-planning-inf-rollback-window. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-upgrade-planning-inf-rollback-window

BibTeX

@misc{warmtransfer-claim-cucm-upgrade-planning-inf-rollback-window,
  title  = {Planning a Unified CM upgrade: source note cucm-upgrade-planning-inf-rollback-window},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cucm-upgrade-planning-inf-rollback-window},
  note   = {Source note cucm-upgrade-planning-inf-rollback-window, checked 2026-09-25}
}

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