# Unified CM backup and upgrade Canonical: https://warmtransfer.net/knowledge/cucm-backup-upgrade Last verified: 2026-09-24 Cisco Unified Communications Manager (Unified CM) upgrades and backups rely on structured pre-upgrade validation, the Disaster Recovery System (DRS), and version-switching mechanisms[^35][^20][^59]. Destination versions such as Release 15 dictate specific upgrade types, hypervisor requirements, and operational sequencing across cluster nodes[^31][^60][^23]. ## Upgrade Types and Paths A direct standard upgrade upgrades the application software but not the underlying operating system[^56]. In contrast, a direct refresh upgrade upgrades both the application software and the underlying operating system[^38]. For Unified CM and IM and Presence Service Release 15 and later, there are no supported Direct Refresh Upgrade paths[^31]. A direct standard upgrade to Release 15 is supported from Unified CM Release 12.5 and from Release 14 and its SUs[^9]. However, an upgrade from Release 14SU4 to a destination version lower than Release 15SU2 is not supported[^1]. For legacy systems running Unified CM 7.0(1) and older, migration to Release 15 is not supported, and Cisco recommends rebuilding on the latest release from scratch[^27]. Every supported path to Release 15 that uses the Prime Collaboration Deployment (PCD) Upgrade Task or PCD Migration Task must use PCD Release 15[^33]. ## Pre-Upgrade Requirements Upgrading requires at least 25G of free space on the common partition[^5]. In addition, the partition must have no expired certificates, including trust certificates[^30]. Every supported upgrade path to Release 15 in the compatibility matrix requires running the pre-upgrade-check COP file first[^35]. After this COP file is installed, its report can be viewed from the CLI using `file view install PreUpgradeReport.txt`[^36]. Cisco also strongly recommends running the upgrade readiness COP file prior to upgrading to reduce the chance of upgrade failure[^37]. Additional administrative preparation includes: - Taking a fresh Disaster Recovery System backup, as an outdated backup can cause data loss or make the system impossible to restore[^20]. - Separately backing up custom ringtones and background images, which are not included in system backups[^47]. - Recording the registered device count with RTMT so endpoints can be checked after the upgrade[^48]. - Setting up a Customer Smart Account and creating a Virtual Account for Smart Licensing[^52]. ## Upgrade Execution and Version Switching Upgrade software can be loaded from DVD/CD, from the local filesystem, or from an SFTP server whose directory, address, and credentials are supplied by the administrator[^58]. The SFTP server bundled with PCD is the only SFTP server Cisco provides, tests, and fully supports through TAC; third-party SFTP servers are not officially supported by TAC[^49]. The Clusterwide Upgrade option is available only for direct standard upgrades where the pre-upgrade version is at least 12.5(1)[^4]. Cisco defines version switching as installing the new version as an inactive version, then switching to it and reverting to the old version whenever the administrator chooses[^59]. During an upgrade, the administrator can select an option to switch to the new version automatically upon completion, though the default is not to switch automatically[^2]. Version switching is supported for direct standard upgrades, but it is not supported for migrations such as the PCD Migration Task[^32]. WarmTransfer's reading of the sources is that a cluster on 11.5 or earlier cannot use version switching to revert if a move to Release 15 fails, because its only paths to 15 are migrations or a fresh install[^25]. When switching versions in a deployment with IM and Presence Service nodes, the Unified CM nodes must be switched first: the publisher, followed by the subscribers[^23]. If this switch order is not followed, some Software Upgrades menu pages will not display or work for the IM and Presence nodes[^22]. If reverting a cluster to the previous version, switch back the publisher first, then all backup subscriber nodes, and finally all primary subscriber nodes[^57]. After reverting, database replication must be reset manually via the CLI command `utils dbreplication reset all`[^46]. ## Disaster Recovery System Backups DRS requires all cluster nodes to run the same version[^17]. Backups should be stored on a network device, as virtualized deployments do not support tape drives[^14]. DRS supports up to 10 backup devices[^10]. For network backup devices, the "Number of backups to store on Network Directory" setting controls how many backup sets are retained[^16]. Backups sent to a remote server that do not finish within 20 hours will time out[^11]. DRS encrypts backup files with a randomly generated password, which is encrypted using the cluster security password[^13]. The cluster security password in effect at backup time is required to restore the files[^13]. No OS Administration tasks should be performed while a backup is running because DRS locks the platform API and blocks OS Administration requests[^15]. DRS operations can also be driven from the CLI using the `utils disaster_recovery` command family, which includes `device add network`, `backup network`, `status backup`, and `schedule add and enable`[^12]. ## DRS Restore Procedures A DRS restore requires the target server's IP address, hostname, DNS configuration, and deployment type to match the values stored in the backup file[^42]. It also requires the version saved in the backup file to match the version running on the nodes, including the full version string with service updates[^45]. WarmTransfer's reading of the sources is that a DRS backup taken prior to an upgrade cannot be restored onto a cluster that has switched to the new version; restoring it requires a node on the exact pre-upgrade version[^26]. If the cluster security password changed after the backup was created, the restore fails unless the old password is available[^43]. During cluster restoration, the publisher (first node) must be restored before subscriber nodes, and it must be restarted before subsequent nodes[^44]. Depending on the database size and selected components, a restore can take a few hours, and database replication after restarting subsequent nodes may take several hours depending on cluster size[^41]. After restoration, replication should be verified on every node with `utils dbreplication runtimestate`; the Replication Status value should be 2 on each node[^40]. ## Licensing Considerations In Unified CM Release 12.0(1) and later, Cisco Smart Software Licensing replaces Prime License Manager (PLM)[^54]. In older PLM 11.5(1) deployments, license migration applied when upgrading an instance from 8.x or earlier to 9.x or later[^34]. Unified CM can be registered to Smart Licensing from the CLI using `license smart register idtoken` followed by a token from Cisco Software Central[^53]. The IM and Presence Service requires no server or software version licenses; users are enabled individually[^21]. After installation, Unified CM operates under a 90-day evaluation period[^18]. While running in this evaluation period, secure SIP trunks cannot be deployed[^19]. Once the 90 days end, adding new users or devices is blocked until the system registers with Cisco Smart Software Manager or a satellite[^18]. Starting in Release 14SU4 and 15SU2, Call Home is deprecated as the Smart Licensing transport and Smart Transport is introduced[^3]. After an upgrade, Unified CM transitions automatically to Smart Transport if `smartreceiver.cisco.com` is reachable, and falls back to Call Home if that connection fails[^55]. ## Applicability Applies to: Cisco Unified Communications Manager, Cisco IM, Cisco Prime Collaboration Deployment, and Cisco Prime License Manager. Deployments: on-premises. Sources checked 2026-09-24. Unified CM Release 15 supports virtualized deployments only, and bare-metal servers are not supported[^60]. Direct standard upgrades to Release 15 are supported from Release 12.5 and Release 14 and its SUs, while upgrades from Release 14SU4 require at least Release 15SU2 as the destination[^9][^1]. Unified CM 7.0(1) and older cannot be migrated to Release 15[^27]. ## What remains uncertain Whether the `utils disaster_recovery` CLI command syntax remains unchanged or fully supported in Release 15 is not covered by the sources below. ## Sources [^1]: An upgrade from Release 14SU4 to a destination version lower than Release 15SU2 is not supported. Source: [Compatibility Matrix for Cisco Unified Communications Manager and the IM and Presence Service, Release 15x](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/compat/15_x/cucm_b_compatibility-matrix-cucm-imp-15x.html), Table 1, Release 14 and SUs row note. Checked 2026-09-24. [^2]: During an upgrade the administrator can choose to switch to the new version automatically when the upgrade completes; the default is not to switch automatically. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, upgrade procedure step for switching versions automatically. Checked 2026-09-24. [^3]: From Release 14SU4 and 15SU2 onward, Call Home is deprecated as the Smart Licensing transport and Smart Transport is introduced. Source: [System Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Smart Software Licensing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01.html), Smart Software Licensing chapter, Smart Transport section. Checked 2026-09-24. [^4]: The Clusterwide Upgrade option is available only for direct standard upgrades where the pre-upgrade version is at least 12.5(1). Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, Clusterwide Upgrade (simplified upgrade) section. Checked 2026-09-24. [^5]: Upgrading requires at least 25G of free space on the common partition. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, check available common partition space task. Checked 2026-09-24. [^6]: An upgrade counts as complete only when every cluster node has installed the new version as inactive, switched version and rebooted, and database replication has completed. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, upgrade terminology / upgrade process overview. Checked 2026-09-24. [^7]: The fresh install with data import path to Release 15 uses the COP file ciscocm.DataExport_v1.0.cop.sgn on the source cluster. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, fresh install with data import rows. Checked 2026-09-24. [^8]: The Release 15 guide lists ciscocm.CSCwi52160_15-direct-migration_v1.0.k4.cop.sha512 as mandatory for migrations from 10.x through 14.x to Release 15. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, COP file column (migration rows). Checked 2026-09-24. [^9]: A direct standard upgrade to Release 15 is supported from Unified CM Release 12.5 and from Release 14 and its SUs. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table. Checked 2026-09-24. [^10]: The Disaster Recovery System supports up to 10 backup devices. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Configure Backup Devices. Checked 2026-09-24. [^11]: A backup to a remote server that has not finished within 20 hours times out. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), View Current Backup Status (caution). Checked 2026-09-24. [^12]: DRS can be driven from the CLI with the utils disaster_recovery command family, including device add network, backup network, status backup, and schedule add and enable. Source: [Configure and Troubleshoot Cisco Unified Communication Manager (CUCM) Backups](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/214287-configure-and-troubleshoot-cisco-unified.html), Configure section, CLI configuration. Checked 2026-09-24. [^13]: DRS encrypts backup files with a randomly generated password, which is itself encrypted with the cluster security password. The security password in effect at backup time is needed to restore. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Backup overview, encryption note. Checked 2026-09-24. [^14]: DRS backups should be stored on a network device; virtualized deployments do not support tape drives. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Backup prerequisites. Checked 2026-09-24. [^15]: No OS Administration tasks should be performed while a backup is running, because DRS locks the platform API and blocks OS Administration requests. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Backup restrictions / prerequisites. Checked 2026-09-24. [^16]: A DRS network backup device has a 'Number of backups to store on Network Directory' setting that controls how many backup sets are kept. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Configure Backup Devices. Checked 2026-09-24. [^17]: DRS requires all cluster nodes to run the same version. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Backup prerequisites. Checked 2026-09-24. [^18]: After installation Unified CM runs under a 90-day evaluation period. When it ends, Unified CM stops allowing new users or devices to be added until it is registered with Cisco Smart Software Manager or a satellite. Source: [System Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Smart Software Licensing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01.html), Smart Software Licensing chapter, evaluation period. Checked 2026-09-24. [^19]: A secure SIP trunk cannot be deployed while Unified CM is running in the 90-day evaluation period. Source: [System Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Smart Software Licensing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01.html), Smart Software Licensing chapter, evaluation period. Checked 2026-09-24. [^20]: A fresh Disaster Recovery System backup should be taken before upgrading, because an outdated backup can cause data loss or make the system impossible to restore. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, back up the system task. Checked 2026-09-24. [^21]: The IM and Presence Service needs no server license or software version license; users are enabled for it individually. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, licensing requirements. Checked 2026-09-24. [^22]: If the Unified CM-before-IM and Presence switch sequence is not followed, some Software Upgrades menu pages will not display or work for the IM and Presence nodes. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, upgrade sequence requirements (note following the switch order). Checked 2026-09-24. [^23]: Before switching versions on IM and Presence Service nodes, the Unified CM nodes must be switched first: the publisher, then the subscribers. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, upgrade sequence requirements. Checked 2026-09-24. [^24]: When IM and Presence is upgraded from 12.5.x or 14.x to 15 or later with PCD, the guide lists the COP file ciscocm.imp15_upgrade_v1.0.k4.cop.sha512. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, IM and Presence rows. Checked 2026-09-24. [^25]: A cluster on 11.5 or earlier cannot use switch version to go back if a move to Release 15 fails, because its only paths to 15 are migrations or a fresh install, and version switching is not supported for migrations (inferred). Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, version switching column. Checked 2026-09-24. [^26]: A DRS backup taken before an upgrade cannot be restored onto the cluster after it has switched to the new version; restoring it needs a node on the exact pre-upgrade version (inferred). Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore prerequisites (version match). Checked 2026-09-24. [^27]: Unified CM 7.0(1) and older cannot be migrated to Release 15; Cisco recommends rebuilding on the latest release from scratch. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrading from Legacy Releases](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrading-from-legacy-releases.html), Upgrading from Legacy Releases chapter, 7.0(1) and older. Checked 2026-09-24. [^28]: Unified CM 8.0(1) and 9.1 must first be migrated directly to 12.5 with PCD 12.6 (not PCD 14 or 15) before moving on to the current release. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrading from Legacy Releases](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrading-from-legacy-releases.html), Upgrading from Legacy Releases chapter, 8.0(1) and 9.1 path. Checked 2026-09-24. [^29]: A direct upgrade to Release 15 is not supported from Unified CM 10.0 through 11.5. Those sources reach 15 by a PCD migration or by a fresh install with data import. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table. Checked 2026-09-24. [^30]: Before upgrading, the partition must have no expired certificates, including trust certificates. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, check for expired certificates task. Checked 2026-09-24. [^31]: There are no Direct Refresh Upgrade supported paths to Unified CM and IM and Presence Service Release 15 and later. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths discussion. Checked 2026-09-24. [^32]: Version switching is supported for direct standard upgrades but not for migrations such as the PCD Migration Task. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, version switching column. Checked 2026-09-24. [^33]: Every supported path to Release 15 that uses the PCD Upgrade Task or the PCD Migration Task must use PCD Release 15. Source: [Compatibility Matrix for Cisco Unified Communications Manager and the IM and Presence Service, Release 15x](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/compat/15_x/cucm_b_compatibility-matrix-cucm-imp-15x.html), Supported upgrade paths section, note under Table 1. Checked 2026-09-24. [^34]: In Prime License Manager 11.5(1), license migration applies when a product instance such as Unified CM is upgraded from 8.x or earlier to 9.x or later. Source: [Cisco Prime License Manager User Guide, Release 11.5(1) - License Management](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/plm/11_5_1/userguide/CPLM_BK_CE0970F4_00_user-guide-rel-1151/CPLM_BK_CE0970F4_00_user-guide-rel-1151_chapter_0101.html), License Management chapter, license migration. Checked 2026-09-24. [^35]: Every supported upgrade path to Release 15 in the compatibility matrix requires running the pre-upgrade-check COP file first. Source: [Compatibility Matrix for Cisco Unified Communications Manager and the IM and Presence Service, Release 15x](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/compat/15_x/cucm_b_compatibility-matrix-cucm-imp-15x.html), Table 1. Supported Upgrade Paths and COP Files for Cisco Unified Communications Manager and the IM and Presence Service. Checked 2026-09-24. [^36]: After the pre-upgrade check COP file is installed, its report can be viewed from the CLI with file view install PreUpgradeReport.txt. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, install COP files procedure. Checked 2026-09-24. [^37]: Cisco strongly recommends running the upgrade readiness COP file before upgrading to reduce the chance of an upgrade failure. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, run upgrade readiness COP file task. Checked 2026-09-24. [^38]: A direct refresh upgrade upgrades both the application software and the underlying operating system. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 12.5(1) - Upgrade Planning](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/12_5_1/cucm_b_upgrade-migration-guide-125x/cucm_b_upgrade-guide-1251su2_chapter_00.html), Upgrade Planning chapter, upgrade types. Checked 2026-09-24. [^39]: For a 12.5(x) destination, sources on 10.5(x), 11.x and 12.0(x) take a direct refresh upgrade, while 12.5(x) to 12.5(y) is a standard upgrade. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 12.5(1) - Upgrade Planning](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/12_5_1/cucm_b_upgrade-migration-guide-125x/cucm_b_upgrade-guide-1251su2_chapter_00.html), Upgrade Planning chapter, supported upgrade paths table. Checked 2026-09-24. [^40]: After a restore, replication should be checked on every node with utils dbreplication runtimestate; the Replication Status value should be 2 on each node. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, post-restore replication check. Checked 2026-09-24. [^41]: A restore can take a few hours depending on database size and the components chosen, and replication after the subsequent nodes restart may take several hours depending on cluster size. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore procedure notes. Checked 2026-09-24. [^42]: A DRS restore requires the target server's IP address, hostname, DNS configuration and deployment type to match those stored in the backup file. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore prerequisites. Checked 2026-09-24. [^43]: If the cluster security password has changed since the backup was taken, the restore fails unless the old password is available. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore prerequisites. Checked 2026-09-24. [^44]: In a DRS restore the publisher (first node) is restored before the subscriber nodes, and the first node must be restarted before the subsequent nodes. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore first node / restore subsequent nodes procedures. Checked 2026-09-24. [^45]: A DRS restore requires the version saved in the backup file to match the version running on the cluster nodes, including the full version string with service updates. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Restore the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_restore-the-system.html), Restore the System chapter, restore prerequisites. Checked 2026-09-24. [^46]: After reverting to the previous version, database replication must be reset manually with the CLI command utils dbreplication reset all. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, revert procedure, reset database replication step. Checked 2026-09-24. [^47]: Custom ringtones and background images are not included in system backups and must be backed up separately before an upgrade. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, back up custom ringtones and background images task. Checked 2026-09-24. [^48]: Cisco's pre-upgrade tasks include recording the registered device count with RTMT so endpoints can be checked after the upgrade. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, record the registered device count task. Checked 2026-09-24. [^49]: The SFTP server bundled with Prime Collaboration Deployment is the only SFTP server that Cisco provides and tests and that Cisco TAC fully supports. Other third-party SFTP servers are not officially supported by TAC. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), SFTP server support section. Checked 2026-09-24. [^50]: The DRS backup device needs write access to the SFTP directory path, and the DRS Master Agent validates the username, password, server name and directory path when the device is configured. Source: [Administration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Back Up the System](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/adminGd/cucm_b_administration-guide-15/cucm_m_back-up-the-system-14.html), Configure Backup Devices. Checked 2026-09-24. [^51]: For 12.5.x sources, the Release 15 guide points to the COP file ciscocm.enable-sha512sum-2021-signing-key-v1.0.cop.sgn for SHA-512 signing support. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, supported upgrade paths table, COP file column. Checked 2026-09-24. [^52]: The pre-upgrade tasks for Release 15 include setting up a Customer Smart Account and creating a Virtual Account for Smart Licensing. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Pre-Upgrade Tasks (Manual Process)](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_pre-upgrade-tasks-15.html), Pre-Upgrade Tasks chapter, Smart Licensing prerequisite. Checked 2026-09-24. [^53]: Unified CM can be registered to Smart Licensing from the CLI with license smart register idtoken followed by a token generated in Cisco Software Central. Source: [Configure CUCM Smart Licensing - Direct Model](https://www.cisco.com/c/en/us/support/docs/unified-communications/unified-communications-manager-callmanager/212915-configure-cucm-smart-licensing-direct.html), Configure section, registration steps. Checked 2026-09-24. [^54]: Cisco Smart Software Licensing replaces Prime License Manager in Unified CM Release 12.0(1) and later. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 12.5(1) - Upgrade Planning](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/12_5_1/cucm_b_upgrade-migration-guide-125x/cucm_b_upgrade-guide-1251su2_chapter_00.html), Upgrade Planning chapter, licensing requirements. Checked 2026-09-24. [^55]: After an upgrade, Unified CM moves to Smart Transport automatically if it can reach smartreceiver.cisco.com, and falls back to Call Home if that connection fails. Source: [System Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Smart Software Licensing](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15/cucm_b_system-configuration-guide-14_chapter_01.html), Smart Software Licensing chapter, Smart Transport section. Checked 2026-09-24. [^56]: A direct standard upgrade upgrades the application software but not the underlying operating system. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 12.5(1) - Upgrade Planning](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/12_5_1/cucm_b_upgrade-migration-guide-125x/cucm_b_upgrade-guide-1251su2_chapter_00.html), Upgrade Planning chapter, upgrade types. Checked 2026-09-24. [^57]: When reverting a cluster, switch back the publisher first, then all backup subscriber nodes, then all primary subscriber nodes. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, revert (switch back) procedure. Checked 2026-09-24. [^58]: Upgrade software can be loaded from DVD/CD, from the local filesystem, or from an SFTP server whose directory, address and login credentials the administrator supplies. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Upgrade Tasks](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_upgrade-tasks.html), Upgrade Tasks chapter, upgrade procedure, Source field options. Checked 2026-09-24. [^59]: Cisco defines version switching as installing the new version as an inactive version, then switching to it and reverting to the old version whenever the administrator chooses. Source: [Upgrade and Migration Guide for Cisco Unified Communications Manager and the IM and Presence Service, Release 15 and SUs - Planning the Upgrade](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/15/cucm_b_upgrade-and-migration-guide_15/cucm_m_planning-the-upgrade-15.html), Planning the Upgrade chapter, version switching column definition. Checked 2026-09-24. [^60]: Unified CM Release 15 supports virtualized deployments only; bare-metal servers are not supported. Source: [Compatibility Matrix for Cisco Unified Communications Manager and the IM and Presence Service, Release 15x](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/compat/15_x/cucm_b_compatibility-matrix-cucm-imp-15x.html), Virtualization requirements section. Checked 2026-09-24.