System Requirements for Cisco Unity Connection Release 15SU5 is available at https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/requirements/b_15cucsysreqs.html.

The Compatibility Matrix for Cisco Unity Connection lists the most recent version combinations qualified to use for Cisco Unity Connection, and Unity Connection and with Cisco Business Edition (where applicable) at

http://www.cisco.com/en/US/products/ps6509/products_device_support_tables_list.html.

This section contains procedures for determining the version in use for the following software:

• Determine Version of Cisco Unity Connection Application
• Determine Version of Cisco Personal Communications Assistant Application
• Determine Version of Cisco Unified Communications Operating System

Cisco Unity Connection Release 15SU5 adds support for VMware by Broadcom ESX 9.0 and 9.1 on VMware vSphere Foundation (VVF) 9.0 and 9.1, and VMware Cloud Foundation (VCF) 9.0 and 9.1. Support for ESX 9.0 and 9.1 is limited to non-appliance hardware.This release also adds support for Nutanix AHV 11.0 with AOS 7.5 on Cisco UCS end-to-end hardware. Supported versions include AHV 11.0.1.1 with AOS 7.5.1.2 and Prism Central 7.5.1.4.

For more information, see:

• Cisco Virtualization Guide for Cisco On-premises Calling Applications

• Install, Upgrade, and Maintenance Guide for Cisco Unity Connection Release 15

To comply with the Chrome Root Program Policy, public root Certificate Authorities (CAs) included in the Chrome Root Store will be restricted to issuing certificates with only the Server Authentication Extended Key Usage (EKU). This change effectively ends the issuance of certificates containing the Client Authentication EKU. Consequently, public CA servers will cease issuing certificates with Client Authentication EKU by March 2027. The specific transition timelines depend on the individual Certificate Authorities.

For secure SIP and SCCP integrations, Cisco Unity Connection uses Mutual Transport Layer Security (mTLS) connections that require certificates containing both Server and Client Authentication EKUs. If you use a certificate provided by a public root CA that includes only the Server Authentication EKU, the certificate may fail validation. This can lead to authentication issues and disrupt the affected SIP or SCCP integration.

To address these changes, the following enhancements are available in Release 15SU5:

• Segregation of client and server certificates: Cisco Unity Connection supports two separate certificates on the same interface. For example, you can use a Tomcat server certificate (with Server Authentication EKU) and a Tomcat client certificate (with Client Authentication EKU) to facilitate mTLS connections. You must obtain certificates with Client Authentication EKU from either a private PKI or an alternate root CA. For Cisco Unity Connection, the client certificates are named tomcat-client and, when applicable, tomcat-client-ECDSA. For CA-signed certificates, the Tomcat server certificate contains only the Server Authentication EKU, and the Tomcat-client certificate contains only the Client Authentication EKU. Self-signed Tomcat and Tomcat-client certificates contain both EKUs. The same EKU behavior applies to the ECDSA certificates.

• Options to disable Client Authentication EKU checks: This enhancement allows Cisco Unity Connection to ignore the EKU from remote peers (clients) that request a connection using a certificate with only the Server Authentication EKU. This setting also allows Cisco Unity Connection to reuse a Server Authentication EKU-only certificate as a client certificate.

  Note	The remote peer must also support a similar model that ignores the Client Authentication EKU.

Users who use self-signed certificates, certificates issued by private or internal CAs, or public root CAs that do not enforce EKU restrictions can reuse the same certificate for both server and client purposes. This capability helps simplify certificate management by reducing the number of certificates needed.

For more information, see the “Manage Certificates and Certificate Trust Lists” section in the “Security” chapter of the Cisco Unified Communications Operating System Administration Guide for Cisco Unity Connection Release 15.

For descriptions and URLs of Cisco Unity Connection documentation on Cisco.com, see the Documentation Guide for Cisco Unity Connection Release 15. The document is shipped with Unity Connection and is available at https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/requirements/b_15cucsysreqs.html.

For descriptions and URLs of Cisco Unified Communications Manager Business Edition documentation on Cisco.com, see the applicable version of Cisco Business Edition at https://www.cisco.com/c/en/us/support/unified-communications/index.html.