CUCM 12.5 support ended: plan your move to CUCM 15
Desk phone as Microsoft Team Phone

CUCM 12.5 support ended: plan your move to CUCM 15

Cisco’s last date of support for Unified Communications Manager 12.5 passed on 31 August 2025. Since then, 12.5 systems receive no security patches or TAC support. Many organisations still run it, often because the platform simply works. But every month without patches increases the risk on a system that carries all internal and external calls.

Where CUCM 15 stands today

The current maintenance release is CUCM 15 SU4/SU4a (readme published February 2026). It can be installed directly on 12.5(1), 14 and earlier 15 builds; older versions need a migration using Cisco’s Prime Collaboration Deployment (PCD).

Points to check before you upgrade:

  • CPU with AVX support. Since 15 SU3 the virtual machine must expose AVX. VMware EVC baselines set to older CPU generations (such as Westmere) cause installs and upgrades to fail.
  • AMD EPYC hosts. Cisco lists an open caveat (CSCwv44220) where installs or upgrades can hang on some AMD EPYC CPUs.
  • Older phones. Firmware for end-of-support endpoints is no longer included in the ISO for fresh installs or migrations. Check your phone inventory first.
  • New phones. PhoneOS firmware for the 8875 and Desk Phone 9800 series is included as of 15 SU3.
  • Upgrade order. Patch the publisher and TFTP servers first, then the subscribers.

Extension Mobility SSO on CUCM 15

ALM Pro version 6 supports CUCM 15. Customers upgrading from ALM Pro 5 need a new license file, which our support team provides (same business day). We recommend upgrading ALM Pro in the same maintenance window as CUCM, so single sign-on keeps working from day one.

Need help planning your upgrade? Contact our support team or see the administrator guides.

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