In an L2 upgrade of a Unity Connection cluster, do not restart or switch version on the publisher until the subscriber upgrade is complete. After that, switch the publisher first and then the subscriber.

Checked 2026-09-25

do not restart or perform switch version on the publisher server before completing the upgrade on subscriber server otherwise cluster does not function properly.

Vendor

Cisco

Product

Unity Connection

Subsystem

sequencing

Deployment

on-premises

Region

not restricted

Release range

Unity Connection Release 15

Checked

2026-09-25

Sources

• Install, Upgrade and Maintenance Guide for Cisco Unity Connection Release 15 - Upgrading Cisco Unity Connection — Cisco Systems · tier 2 current vendor documentation · Upgrading Cisco Unity Connection > Upgrading a Unity Connection Cluster

Cite this note

APA

WarmTransfer. (2026, September 25). Planning a Unified CM upgrade: source note cucm-upgrade-planning-cuc-l2-switch-caution. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-upgrade-planning-cuc-l2-switch-caution

BibTeX

@misc{warmtransfer-claim-cucm-upgrade-planning-cuc-l2-switch-caution,
  title  = {Planning a Unified CM upgrade: source note cucm-upgrade-planning-cuc-l2-switch-caution},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cucm-upgrade-planning-cuc-l2-switch-caution},
  note   = {Source note cucm-upgrade-planning-cuc-l2-switch-caution, checked 2026-09-25}
}

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