The following table lists the recommended Rommon and CPLD versions for Cisco IOS XE 17.2.x onwards releases.

Note	Cisco 4461 ISR may require two upgrade packages to upgrade to 21102941. See CPLD-4-1 Release Notes.

The hardware-programmable firmware is upgraded when Cisco 4000 Series ISR contains an incompatible version of the hardware-programmable firmware. To do this upgrade, a hardware-programmable firmware package is released to customers.

Generally, an upgrade is necessary only when a system message indicates one of the field-programmable devices on the Cisco 4000 Series ISR needs an upgrade, or a Cisco technical support representative suggests an upgrade.

From Cisco IOS XE Release 3.10S onwards, you must upgrade the CPLD firmware to support the incompatible versions of the firmware on the Cisco 4000 Series ISR. For upgrade procedures, see the Upgrading Field-Programmable Hardware Devices for Cisco 4000 Series ISRs.

There are no new hardware features for this release.

The following features are supported by the Cisco 4000 Series Integrated Services Routers for Cisco IOS XE Bengaluru 17.4.1a:

• BGP Large Community—The BGP large communities are similar attributes to BGP communities. The BGP large communities attribute provides the capability for tagging routes and modifying BGP routing policy on routers. BGP large communities can be appended or removed selectively on the large community attribute as the route travels from router to router.

• Consent Token Authorization Process for Dev Key Access—With the introduction of the dev-key install functionality, a subset of Cisco IOS XE platforms which support dev-key install functionality are shipped only with release public key without a dev public key. With this change in the functionality, an image that is signed with a dev private key will not boot due to the absence of dev public key for image verification.

• CUBE: Hunt Stop for Server Groups—Server groups allow you to create simpler configurations by specifying a list of destination SIP servers for a single dial peer. When a call matches a dial peer that is configured with a server group, the destination is selected from the list of candidates based on a configured policy. If it is not possible to complete that call, the next candidate is selected. Alternatively, you can also choose to stop hunting through the group if a specified response code is received. If the call cannot be placed to any of the servers in the group, or hunting is stopped, call processing continues to the next preferred dial-peer.

• CUBE: VoIP Trace Serviceability Framework—VoIP Trace is a Cisco Unified Border Element (CUBE) serviceability framework, which provides a binary trace facility for persistently monitoring and troubleshooting SIP call issues. The VoIP Trace framework records both successful and failed calls. All call trace data is stored in system memory. In addition, data for calls with IEC errors is written to the logging buffer.

• CUBE: Smart License Using Policy—Smart Licensing using Policy reports license usage periodically based on an account policy, rather than requesting licenses based on past usage as in previous releases. Evaluation mode and license reservation are not supported. Frequent license requests used to go out from a device to CSSM in earlier versions. In the changed scenario, minimum reporting license usage is 8 hours. Now all the devices within a network follow the uniform approach of reporting their license usage to Smart Agent. The Smart Agent in turn creates a Resource Utilization Monitoring (RUM) report and dispatches to CSSM based on the Smart Agent reporting policy

  For a more detailed overview on Cisco Licensing, go to https://cisco.com/go/licensingguide.

• CUBE: Clear Hung RTP Ports—When establishing a call, CUBE allocates several RTP ports that are based on the media that are negotiated for the session. Some ports remain assigned even after the call ends. In the current behavior, show voip rtp statscommand displays only the ports allocated from the global table, even if the ports are allocated from all the three tables (Global port, media IP address-based, and media VRF-based). Now this command is enhanced to display the ports allocated from all the three tables. The command also displays the hung ports and allows you to release those ports. Releasing the hung ports increases the efficiency of the routers as more ports are available to receive calls.

• Change of Authorization and Trustsec—Change of Authorization (CoA) provides a mechanism to change the attributes of an authentication,authorization, and accounting (AAA) session after it is authenticated. Identity-Based Networking Services supports change of authorization (CoA) commands for session query,reauthentication, and termination, port bounce and port shutdown, and service template activation and deactivation.

• Configure Performance Measurement— This feature enables hardware timestamping. The Performance Measurement (PM) for link delay uses the light version of Two-Way Active Measurement Protocol (TWAMP) over IP and UDP.

• Configuring the Same Global Address for Static NAT and PAT— You can now configure the same global address within the static NAT and static PAT. This configuration is supported only on outside static NAT.

• Configuring Stateless Static NAT— Static Network Address Translation (NAT) allows the user to configure one-to-one translations of the inside local addresses to the outside global addresses. A new keyword stateless is introduced for Cisco IOS XE static NAT configuration and it applies only to static NAT command. When the static mapping is set to stateless, no sessions will be created for that traffic flow.

• EPC support on LTE interface and FlexVPN Interface— Embedded Packet Capture (EPC) is an onboard packet capture facility that allows network administrators to capture packets flowing to, through, and from a device. This feature facilitates troubleshooting by gathering information about packet format.

• IP-SLA-HTTPS on ISR— This feature has enhanced capabilities of IP SLA device tracking with HTTPS probes and helps to verify reachability in the network.

• NBAR Support on the EVC Service Instance—To classify the data packets, enable NBAR FIA-trace data for NBAR on the EFP interface. Quality of service (QoS) takes action on the output interface based on the NBAR traffic classification result.

• Unified SRST: Smart License Using Policy—Smart Licensing using Policy reports license usage periodically based on an account policy, rather than requesting licenses based on past usage as in previous releases. Evaluation mode and license reservation are not supported. License usage is reported to Smart Agent three minutes after the last configuration change. Now all the devices within a network follow the uniform approach of reporting their license usage to Smart Agent. The Smart Agent in turn creates a Resource Utilization Monitoring (RUM) report and dispatches to CSSM based on the Smart Agent reporting policy. For more information see the Smart License Using Policy for Unified SRST and Smart License Using Policy for Unified E-SRST guides.

  For a more detailed overview on Cisco Licensing, go to https://cisco.com/go/licensingguide.

• Unified CME: Smart License Using Policy—Smart Licensing using Policy reports license usage periodically based on an account policy, rather than requesting licenses based on past usage as in previous releases. Evaluation mode and license reservation are not supported. License usage is reported to Smart Agent three minutes after the last configuration change. Now all the devices within a network follow the uniform approach of reporting their license usage to Smart Agent. The Smart Agent in turn creates a Resource Utilization Monitoring (RUM) report and dispatches to CSSM based on the Smart Agent reporting policy.

  For a more detailed overview on Cisco Licensing, go to https://cisco.com/go/licensingguide.

• You can use the Web UI to configure Smart Licensing on the Cisco 4000 Series Integrated Services Routers. For more information, see Web UI Online Help.