Release 15 brings an enhanced experience for users and administrators with major platform upgrades to align with the industry standards. Enhancements include Application-layer changes and core Linux transition for long-term support. The enhancements also includes transition to the 64-bit application architecture for removal of memory bottlenecks and mitigating end-of-life for 32-bit dependencies. This release provides enhanced protection, security, innovation, and flexibility.

Some of the important considerations when installing or migrating to Release 15 are:

• Unified Communications Manager and IM and Presence Service 15 requires a minimum ESXi version of 7.0 U3 or 8.0 U1 (see https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-cisco-unified-communications-manager.html#v15) with a minimum VM Hardware version 17. The other required VM specifications like guest OS type may be found in the Readme of the base OVA on software.cisco.com.

• Release 15 of Unified Communications Manager has higher minimum hardware specs than older releases. Use the following to help you identify if you need more usable disk space, memory, or physical CPU cores:

  • https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-cisco-unified-communications-manager.html#v15

  • QuoteCollab Tool

  • Run Upgrade Readiness COP File (Pre-upgrade)

  • Readme of the base OVA for Unified Communications Manager or IM and Presence Service

  Note	Direct upgrade to Unified Communications Manager and IM and Presence Service Release 15 will fail for all single 80GB vDisk deployments, even if you manually resized the HDD size to 110 GB.

• Direct Refresh Upgrades from Pre-12.5.x source to Release 15 is not supported. You might either:

  • First upgrade your source to Release 12.5.x or 14 and SUs and then upgrade your source to Release 15.

  • Use a direct migration method (PCD Migration Task or Fresh Install with Data Import). See the Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service for more details.

• Virtual Floppy Drive is replaced with virtual CDROM for touchless installation.

• Unified Communications Manager and IM and Presence Service 15 supports only Open VM Tools. Fresh install of 15 will install Open VM Tools. Direct upgrade and migration to 15 installs Open VM tools regardless of if the source release was Open VM Tools or VMware Tools. For more information, see the Installation Guide for Cisco Unified Communications Manager and the IM and Presence Service.

• IPSec policy with 3DES Algorithm is not supported in FIPS mode for Release 15 in case you are planning to upgrade or migrate to Release 15. You must delete and recreate the IPSec policy with the Encryption and ESP Algorithms other than 3DES in both the nodes between which the IPSec tunnel is to be established, and then plan an upgrade or migration. For more information, see the Security Guide for Cisco Unified Communications Manager.

• Few of the Unified RTMT counters are updated to 64 bits: Network Interface and Ramfs. See the Cisco Unified Real-Time Monitoring Tool Administration Guide for more information.

• Administrators use trace files to obtain specific information about Unified Communications Manager and IM and Presence Service service-related problems. Cisco Unified Serviceability sends configured trace information to the trace log file. This .gzo file is no longer a compressed file but a text file. Henceforth, .gzo file need not be uncompressed and can be read as plain text. See the Administration Guide for Cisco Unified Communications Manager for more information.

• H.323 Gatekeeper Control options will no longer be available in Unified Communications Manager. Hence, we recommend that you use SIP trunk with Location Bandwidth Manager (LBM). For more information, see the following:.

  • Deprecation of H.323 Gatekeeper Control Options in Cisco Unified Communications Manager, Release 15

  • System Configuration Guide for Cisco Unified Communications Manager

In Unified Communications Manager, you can auto provision the Webex App or Cisco Jabber devices when new LDAP users are synchronized from Microsoft Active Directory. The Write back to LDAP option allows you to write the Primary DN chosen from Unified CM back to the LDAP server. LDAP attributes available for write back are: telephoneNumber, ipPhone, and mobile.

With this release, Webex Calling for Microsoft Teams users can view the call history for their shared devices which are registered to the Unified Communications Manager. For more information, see Webex Call Integration with Microsoft Teams for On-prem UCM.

To use this feature, the Unified Communications Manager node must be onboarded through Webex Cloud-Connected UC.

Microsoft Teams users must use Webex Calling integration for Microsoft Teams. For more information, see Webex Calling integration with Microsoft Teams.

Unified Communications Manager supports certificate revocation list, where the CA will have a list of digital certificates that have been revoked before their actual or assigned expiration date. To enable this feature you have to check the Enable CRL check box and enter the CRL Distribution Point URI from where the CRL files are downloaded.

For detailed information on the certificate revocation list support, see the 'Certificate Revocation Configuration' section in the Security Guide for Cisco Unified Communications Manager.

Unified Communications Manager now makes it easier to specify where cluster nodes will find their ISO files for upgrade or COP files, using the Cluster Software Location menu from the Cisco Unified OS Administration user interface.

In this release, you can centrally manage the Software Location settings for all cluster nodes from the publisher instead of locally on each cluster node.

From Release 12.5(1)SU7a onwards, Unified Communications Manager supports thin-client IPs to be used for device mobility instead of Hosted Virtual Desktop (HVD) IPs for Webex client. However, from Release 14SU3 onwards, the Cisco Unified CM Administration UI displays the HVD IP address, in addition to the thin-client IP address for the Webex Virtual Desktop Infrastructure (VDI) clients. This feature is supported from Webex App VDI version 43.2 onwards. The display of HVD IP address on the UI enables better serviceability and debugging.

OAuth feature is now enhanced to eliminate refresh token dependency on Unified Communications Manager publisher node by providing access to the subscriber node to update the refresh token.

For more information, see the 'System Parameters Task Flow' section of the "Configure Enterprise Parameters and Services" chapter in the System Configuration Guide for Cisco Unified Communications Manager.

The Cisco Unified Communications Manager Administration interface has been enhanced with the following accessibility improvements for various settings:

• Tab sequencing issues are addressed where users can now select the table sequence in order and align the content properly on cucreports.

• Indexing user tab has been enhanced so that the mandatory fields with an asterisk symbol can be viewed by the screen reader users.

• Information sorting in tables using keyboard has been addressed for better readability.

• Fields labels—Accessibility screen readers can now easily read the different fields in the user interfaces.

Webex App is not notified of incoming VoIP call notifications when an iOS device operates in a Wi-Fi constrained network with no internet connection such as, hospitals, cruise ships, airplanes, and so on. Due to lack of internet connectivity, the device does not have access to the Apple Push Notification Service (APNS). Users expect to receive calls without any delay. However, with APNS a call can be delayed for a few seconds when there is a network latency.

With this release, Local Push Notification Service (LPNS) for calls has been introduced for iOS devices. It helps to minimize any delay as the push message is sent to the client through a persistent connection. For more information, see the ‘Local Push Notification Service’ section in the Push Notifications Deployment Guide.

To know the minimum required iOS version for Webex App, see System requirements for Webex services.

Currently, Unified Communications Manager inserts MTP for a DTMF mismatch in both secure and non-secure calls. But for secure calls, though MTP is inserted for a DTMF mismatch, it just passes through the media between the parties. Hence, the DTMF events are not sent between the parties. Before Unified CM Release 14SU3, DTMF translation worked only for non-secure calls when there was an MTP allocated for a DTMF mismatch.

With this release, Unified CM can invoke a hardware MTP (with SRTP DTMF interwork support) for a DTMF mismatch between secure endpoints. For more information, see the 'SRTP DTMF Interworking' section in the "Configure Media Resource" chapter of the System Configuration Guide for Cisco Unified Communications Manager.

From this release onwards, you can install Cisco Unified Real-Time Monitoring Tool (Unified RTMT) on workstations running on both Windows or Linux operating systems using a single 'CiscoRTMTPlugin.zip' plug-in. This feature enhancement takes away the need for a separate plug-in (.exe installer for 32 and 64 bit) for Windows and Linux platforms.

Unified RTMT installation is now supported on computers running on the Windows 11 operating system.

Unified RTMT certificate-based authentication support

In this release, Unified RTMT supports Certificate-based authentication that provides enhanced security considerations. Using this authentication method, it reduces the threat of compromised passwords, and provides protection of sensitive or classified components in your network infrastructure.

Unified Communications Manager supports the automatic renewal of refresh token for Webex clients. This feature introduces a new enterprise parameter ‘Auto Renew Refresh Token’ that is enabled by default.

For more information, see:

• System Parameters Task Flow section of the 'Configure Enterprise Parameters and Services' chapter in the System Configuration Guide for Cisco Unified Communications Manager

• OAuth Framework section of the 'Identity Management' chapter in the Security Guide for Cisco Unified Communications Manager

Unified Communications Manager Release 15 does not support Remote Call Control with Microsoft Lync Server for IM and Presence Service. If you are using this feature currently in your deployment and you are trying to upgrade to Release 15, you cannot use this feature after the upgrade.

Note	This feature continues to be supported in Releases 12.5.x and 14 and SUs until their EOL/EOS.

For more information, see Deprecation of Remote Call Control with Microsoft Lync Server for IM and Presence Service on Cisco Unified Communications Manager, Release 15.

Starting with Release 15 onwards, phone firmware that is end of support will no longer be included in the Unified Communications Manager ISO. These endpoints will still be allowed to register, unless they have been officially deprecated, but the firmware will not be present in the TFTP directory following a fresh install. For more details, see the ReadMe for Cisco Unified Communications Manager.

Location Bandwidth Manager (LBM) running on Unified Communication Manager version 15 cannot communicate with Unified CM versions that are older than Release 15 (For example, 11.5.x, 12.5.x, 14 and SUs) or other clusters with a newer version of Release 15 (for example, Release 15 SU1 or later). Hence, we recommend that you do one of the below if you are using LBM across multiple clusters:

• Upgrade to Release 15SU1 of the Unified Communications Manager, once it becomes available. This version has the fix for the issue as described in CSCwi82830.

• Ensure that you install the ciscocm.V15FCS_CSCwi82830-lbm_C0211-1.cop.sha512 COP file on Unified Communications Manager Release 15 to interoperate with LBM running on Unified Communication Manager versions 11.5.x, 12.5.x, 14 and SUs, 15SU1 or later. You must also install the COP file on all the clusters of Unified CM Release 15 to interoperate with LBM.