Release Notes for UCC SMF and cnSGWc, Release 2026.03.3

First Customer Ship (FCS)

23-July-2026

End of Life (EoL)

23-July-2026

End of Software Maintenance (EoSM)

22-Jan-2028

End of Vulnerability and Security Support (EoVSS)

31-Jan-2028

Last Date of Support (LDoS)

31-Jan-2029

Software Reliability

DNS-based AMF discovery (N11 interface without NRF)

Introduces support for AMF endpoint discovery using DNS-based FQDN generation. This feature removes the mandatory dependency on the NRF for N11 signaling by deriving FQDNs directly from the GUAMI. This enhancement improves latency, supports edge-cloud deployments, and enables seamless AMF discovery in multi-AMF environments.

 Software Reliability

Stabilizing voice call continuity during failed 5G to 4G handover

You maintain voice call continuity and minimize call drops when a 5G to 4G handover fails. Your device can quickly resume 5G voice service with near-instant recovery and improved call stability.

Software Reliability

Dual-Stack UPF tunnel allocation for seamless mobility

In dual-stack configurations, the cnSGW now allocates both IPv4 and IPv6 UPF tunnel endpoints during the SGW relocation procedure. This occurs regardless of the address family used by the incoming eNB F-TEID. By providing both addresses in the Create Session Response, the cnSGW allows the MME to share the appropriate IP version with the target eNB, ensuring seamless handovers during 4G/5G mobility.

Enhanced service request prioritization during 5G-to-4G handovers

Previous Behavior: A Service Request (UE-initiated Idle Mode Exit) arriving during a 5G-to-4G handover without the corresponding Handover Cancel from the access side was rejected by the SMF with an HTTP 400 error. The rejection itself was correct behavior — the failure was caused by the missing Handover Cancel, which left the Service Request colliding with the active handover and led to the voice call drop.

New Behavior: If a service request is received during an ongoing 5G-to-4G handover, the SMF now automatically terminates the pending handover and performs a clean resource teardown. The system then immediately prioritizes and processes the Service Request via an Idle mode exit procedure. If a voice call is active, the SMF also ensures the PCF is updated with the current rule status.

Customer Impact: This change significantly reduces voice call drops and improves call continuity during 5G-to-4G transitions. Operators can expect improved voice call KPIs and a more reliable handoff experience for end-users.

Optimized EDR file transfer to prevent packet drops
[CSCwv61372]

Previous Behavior: In previous releases, the edr-monitoring pod used kubectl exec based commands to copy compressed NAS EDR files from the smf-service pods. This method created excessive processing overhead, leading to a significant increase in packet drops (RX_DROPS) on the physical NIC interfaces of the control plane nodes hosting the edr-monitoring pods.

New Behavior: The system now employs a highly efficient HTTP curl-based transfer method. A new internal endpoint has been implemented on each service pod to facilitate the transfer of EDR records. The edr-monitor pod utilizes this endpoint to retrieve files, replacing the previous resource-intensive process.

Customer Impact: This optimization improves system stability and network performance by significantly reducing the RX_DROPS previously caused by the EDR file transfer process. The change is transparent to the end-user, and the final delivery of EDRs to external storage remains unchanged.

Improved error handling for N11 release and N1N2 failure scenarios
[CSCww09564]

Previous Behavior: During "Create-over-Create" (5G to 4G) transitions, a collision could occur if an N11 release was received from the AMF. Because 5G cleanup is asynchronous and fast, the N11 release often arrived when the context was already cleared or while 4G establishment was underway, causing the SMF to return an HTTP 500 error. Similarly, "UE-unreachable" N1N2 failure notifications during initial 5G setup were often left unprocessed, leading to subsequent release collisions and HTTP 500 errors.

New Behavior: SMF now returns a successful HTTP 204 response for N11 release messages if the context is already in an IDLE or released state, or if the session is currently transitioning to 4G. Additionally, the SMF now correctly processes "UE-unreachable" N1N2 failure notifications, providing a successful acknowledgment and triggering a controlled session cleanup.

Customer Impact: This change improves session stability by significantly reducing unnecessary HTTP 500 error responses during 4G/5G mobility and failed 5G setups. It ensures more robust cleanup handling during race conditions, while the standard release behavior for established sessions remains unchanged.

CSCwu87850

gtpc s11 pod go routine constantly showing high during longevity run post SMI upgrade.

CSCwv49132

Mobility-collision - NR to LTE colliding between NR to Wifi CSR and CBR.

CSCwv61372

Rx_drops increased after enabling NAS EDR in SMF.

CSCwv74363

Multi-party call issue.

CSCwv91480

Show NRF commands are not working and application communication failure.

CSCww09358

IM exit colliding with N7 delete, upon guard time expiry Rulereport sent to PCF.

CSCww09564

N11 SM release failure increased post upgrade.

CSCww19208

Voice-collision UE init mod req - semantic error results in flow deletion.

CSCww32306

Voice call failure during transition from idle to active state.

CSCww55257

CPU utilization for S11 GTPC pod has been increased by 200% more post July '26 SMI upgrade.

CSCww55150

S11 MB Response latency has increased after upgrading to July '26 SMI.

Ultra Cloud Core SMI

2026.03.1.08

Ultra Cloud CDL

2.3.0

Ultra Cloud Core UPF

2026.03.0

Ultra Cloud cnSGWc

2026.03.3

ccg-2026.03.3.SPA.tgz

The SMF and cnSGWc offline release signature package. This package contains the SMF deployment software, NED package, as well as the release signature, certificate, and verification information.

2026.03.3

ncs-6.4.8.3-ccg-nc-1.1.2026.03.3.tar.gz

The NETCONF NED package. This package includes all the yang files that are used for NF configuration.

Note that NSO is used for the NED file creation.

6.4.8.3

ncs-6.1.14-ccg-nc-1.1. 2026.03.3.tar.SPA.tgz

6.1.14

Microsoft Windows

Open a command line window and type the following command:

> certutil.exe -hashfile <filename.extension> SHA512

Apple MAC

Open a terminal window and type the following command:

$ shasum -a 512 <filename.extension>

Linux

Open a terminal window and type the following command:

$ sha512sum <filename.extension>

OR

$ shasum -a 512 <filename.extension>

Note:      <filename> is the name of the file. <extension> is the file type extension (for example, .zip or .tgz).

SMF documentation

Session Management Function

cnSGWc documentation

Serving Gateway Function

SMI documentation

Subscriber Microservices Infrastructure

UPF documentation

User Plane Function

Service request and additional information

Cisco Support