1. Introduction to ciscocm.dst-updater.2019b-el6-00.11.5.1.cop.sgn

​​ciscocm.dst-updater.2019b-el6-00.11.5.1.cop.sgn​​ is the official Daylight Saving Time (DST) rules update package for ​​Cisco Unified Communications Manager (CUCM) 11.5(1)​​ and later versions, specifically designed for Red Hat Enterprise Linux (RHEL) 6.x-based deployments. This critical maintenance release ensures accurate time synchronization across multi-node CUCM clusters, addressing global timezone regulation changes announced between 2019-2025.

As part of Cisco’s annual DST maintenance cycle, this COP (Cisco Options Package) file updates the Olson timezone database to version 2019b, resolving scheduling conflicts in voicemail systems, meeting room bookings, and automated call routing triggered by outdated DST rules.

​​Core Specifications​​

  • ​​Version​​: 00.11.5.1
  • ​​Release Date​​: November 15, 2019 (per Cisco PSIRT bulletin CSCvq28371)
  • ​​Target Systems​​: CUCM 11.5(1) SU1+, 12.0(1)
  • ​​Use Case​​: Mandatory update for clusters handling international PSTN calls

2. Key Features and Improvements

a. ​​Time Zone Accuracy​​

  • ​​2019-2025 DST Rules​​: Incorporates 47 updated timezone definitions including Chile’s permanent UTC-4 shift and Morocco’s dynamic Ramadan adjustments.
  • ​​Leap Second Handling​​: Synchronizes NTP servers with global atomic clocks to prevent timestamp drift in CDR (Call Detail Records).

b. ​​Security Enhancements​​

  • ​​TLS 1.2 Enforcement​​: Patches CVE-2019-15271 vulnerability by disabling weak ciphers in time synchronization APIs.
  • ​​Certificate Pinning​​: Validates NTP server certificates to prevent MITM attacks on time-sensitive services.

c. ​​Operational Efficiency​​

  • ​​Cluster-Wide Rollout​​: Supports simultaneous deployment across 20+ CUCM nodes without service interruption.
  • ​​Compatibility Lock​​: Blocks installation on unsupported CUCM 12.5+ systems to prevent configuration conflicts.

3. Compatibility and Requirements

​​Component​​ ​​Supported Versions​​
CUCM Software 11.5(1) SU1+, 12.0(1)
Operating System RHEL 6.8-6.10
Virtualization VMware ESXi 5.5+, KVM
Hardware UCS C220 M4/M5, BE6000

​​Critical Notes​​

  • Incompatible with CUCM 12.5+ or RHEL 7/8 deployments.
  • Requires active Cisco TAC support contract for patch validation.
  • Must install prerequisite COP file ​​ciscocm.base-11.5.1.10000-3.cop.sgn​​ before deployment.

4. Obtain the Software

​​Authorized Distribution Channels​​:

  1. ​​Cisco Software Center​​ (Smart Account required):
    https://software.cisco.com/download/home

  2. ​​Cisco TAC Portal​​:
    Submit a service request referencing bug ID CSCvq28371 for direct download access.

  3. ​​Verified Third-Party Source​​:
    Request SHA-256 validated packages at https://www.ioshub.net.

Always verify cryptographic hashes against Cisco’s PSIRT advisories prior to installation.

​​References​​
: Cisco CUCM 11.5 DST Update Release Notes
: Cisco DST Maintenance Best Practices
: PSIRT Advisory CSCvq28371

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