8800-series phones of hardware version V15 or later need at least MPP firmware 11.3.3 and cannot downgrade to earlier MPP firmware; the 8821 and 8831 cannot be migrated.

Checked 2026-09-24

Vendor
Cisco
Product
Cisco IP Phone 8800
Subsystem
device migration
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-24
Checked
2026-09-24

Sources

Cite this note

APA

WarmTransfer. (2026, September 24). Building a hybrid Unified CM and Webex Calling environment for a phased migration: source note cucm-webex-calling-hybrid-build-8800-v15-no-downgrade. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-webex-calling-hybrid-build-8800-v15-no-downgrade

BibTeX

@misc{warmtransfer-claim-cucm-webex-calling-hybrid-build-8800-v15-no-downgrade,
  title  = {Building a hybrid Unified CM and Webex Calling environment for a phased migration: source note cucm-webex-calling-hybrid-build-8800-v15-no-downgrade},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cucm-webex-calling-hybrid-build-8800-v15-no-downgrade},
  note   = {Source note cucm-webex-calling-hybrid-build-8800-v15-no-downgrade, checked 2026-09-24}
}

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