Wi-SUN SDK Version 2.11.0 - Release Notes (Mar 25, 2026)#

Wireless Smart Ubiquitous Network (Wi-SUN) is the leading IPv6 sub-GHz mesh technology for smart city and smart utility applications. Wi-SUN brings Smart Ubiquitous Networks to service providers, utilities, municipalities/local government, and other enterprises by enabling interoperable, multi-service, and secure wireless mesh networks. Wi-SUN can be used for large-scale outdoor IoT wireless communication networks in a wide range of applications covering both line-powered and battery-powered nodes.

Silicon Labs' Wi-SUN hardware is certified by the Wi-SUN Alliance, a global industry association devoted to seamless LPWAN connectivity. Wi-SUN builds upon open standard internet protocols (IP) and APIs, enabling developers to extend existing infrastructure platforms to add new capabilities. Built to scale with long-range capabilities, high-data throughput, and IPv6 support, Wi-SUN simplifies wireless infrastructure for industrial applications and the evolution of smart cities.

Release Summary#

Key Features | API Changes | Bug Fixes | Chip Enablement

Key Features#

Added in 2.11.0#

• Expanded RF test component with TX and RX modes.

  Added dedicated transmission and reception test modes to the wisun_rf_test component to support high-volume production testing.

• Reduced authenticator heap usage.

  Reduced authenticator heap usage to support larger networks on memory-constrained SoC Border Routers. On a network with 250 nodes, this saves approximately 125 KB of heap on the authenticator.

Added in 2.10.0#

• Significant RPL performance improvements and enhanced network stability.

  Major enhancements to the RPL routing protocol including improved parent selection, better handling of metric updates, optimized DAO transmission, and more resilient network topology management.

• Enhanced LFN support.

  Improved reliability of LFN transmissions, better parenting features, and optimized retry policy.

• NCP application.

  Release of Wi-SUN NCP (Network Co-Processor) application for evaluation purposes.

• New border router sample applications.

  • Wi-SUN SoC Border Router Empty.

  • Wi-SUN SoC Border Router In Meter Gateway.

  • Wi-SUN SoC Border Router Agent.

• Significant memory footprint reduction.

• FAN 1.0 certification support

  Various updates to ensure full compliance with FAN 1.0 certification requirements, enabling devices to successfully pass FAN 1.0 certification testing.

API Changes#

Changed in 2.11.0#

Modified sl_wisun_phy_config_explicit_t to include a channel_mask field to restrict the set of channels used for transmission.

Changed in 2.10.0#

None.

Bug Fixes#

Fixed in 2.11.0#

• Fixed an issue where a node could remain stuck in Join State 4 (Parent Selection) and fail to select a parent until PAN timeout.

• Fixed an issue where post-reboot DAOs could be dropped, preventing RPL route establishment.

• Fixed connection failures with certain OFDM PHY configurations generated by the Simplicity Studio radio configurator.

• Fixed compatibility issue between the WiseConnect extension v4.0.0 and SoC Border Router with Wi-Fi support applications.

Fixed in 2.10.0#

• Fixed authenticator vulnerability to installation of predictable keys.

• Fixed MAC security neighbor table growing beyond configured maximum.

• Fixed several interoperability issues discovered during FAN 1.1 testbed setup.

Chip Enablement#

None.

Key Features#

New Features | Enhancements | Removed Features | Deprecated Features

New Features#

Added in 2.11.0#

• Channel Mask for Explicit Channel Plans

  Added a channel_mask field to sl_wisun_phy_config_explicit_t to restrict the set of channels on which the device is permitted to transmit. The mask applies to asynchronous, unicast, and broadcast frames, and is advertised in both US-IE and BS-IE.

• Expanded RF Test Component

  Extended the wisun_rf_test component with dedicated TX and RX test modes to support high-volume production testing. The PHY configuration can be selected from the command line.

Added in 2.10.0#

• Security APIs

  • Added sl_wisun_br_revoke_pairwise_keys() and sl_wisun_br_revoke_gtks() APIs to revoke security keys.

  • Added sl_wisun_set_eap_identity() API. It configures the identity that the Border Router or device will present during EAP-TLS authentication. This is part of the certificate-based security handshake. It was previously always set to "anonymous".

• Routing and RPL

  • Added sl_wisun_br_get_routing_table_from_index() API. It allows reading the routing table in chunks, reducing the amount of information that needs to be stored on the stack at any given time.

  • Extended the connection parameter structure sl_wisun_connection_params_t with DAO transmission timing configurations.

• Network Configuration

  • Added sl_wisun_set_regulation_parameters() API. It deprecates sl_wisun_set_regulation() and provides finer control over the regional regulation logic that can be enabled.

  • Added sl_wisun_reset_regulation_duty_cycle() API to reset all past hour transmission counters, useful for testing and debugging regional regulation compliance.

  • Added sl_wisun_set_fan_tps_version() API. It can be used to force the use of FAN 1.0 frame formatting. It should only be used in the context of a FAN 1.0 certification. In practice, using FAN 1.0 is generally unnecessary; FAN 1.1 remains fully compatible with FAN 1.0 and is the recommended default for all deployments. There is no benefit to forcing FAN 1.0 unless a pure FAN 1.0 network is explicitly required or mandated by a certification process.

  • Updated Singapore Channel Plan Id according to Phy TPS 2v04.

• MAC and PHY

  • Extended the connection parameter structure sl_wisun_connection_params_t with MAC configurations. It offers the possibility to fine tune the CSMA-CA parameters and maximum retransmission count.

  • Extended the statistics with the count of packets received using our concurrent detection feature.

• LFN Features

  Extended the LFN connection parameters structure sl_wisun_connection_params_t with EAPoL, traffic and MAC configurations.

• Socket and Network Stack

  • Added sl_wisun_set_rx_fifo_size() API. This API allows configuration of the receive FIFO buffer size. It can be useful to reduce RAM usage when it is known that large packets will not be received by the application. By adjusting the RX FIFO size to match the expected maximum packet size, developers can optimize memory allocation and free up RAM for other purposes. The buffer size should be set according to the application's specific packet size requirements and should be used with care.

  • Added blocking mode support for the TCP connect request.

  • Added DHCP solicit transmission parameters.

• Logging and Diagnostics

  Added event logging APIs (sl_wisun_set_event_filter() and sl_wisun_clear_event_filters()) enabling real-time monitoring of network events such as neighbor lifetime changes, frame reception/transmission, and frame counter failures. Events can be filtered by MAC address and event type and are delivered through Silicon Labs' Event System API.

Enhancements#

Added in 2.11.0#

• LFN Improvements

  • Improved long-term LFN connection stability by adapting the listening strategy based on the parent's measured clock drift.

  • Improved recovery after a parent reboot. LFNs now initiate a new parent selection instead of remaining attached to a parent that no longer recognizes them.

• Security

  • Reduced authenticator heap usage to support larger networks. During authentication, temporary information tied to each supplicant is now freed once they become unnecessary, reducing each supplicant entry from ~700 bytes to ~200 bytes. On a network with 250 nodes, this saves ~125 KB of heap on the authenticator.

  • Improved key rotation robustness to reduce the risk of a device losing connectivity during a key rotation window.

Added in 2.10.0#

• RPL and Routing

  This release introduces significant improvements to the RPL (Routing Protocol for Low-Power and Lossy Networks) implementation, focusing on enhanced network stability, better parent selection logic, and optimized routing efficiency. These changes address edge cases in topology management, improve responsiveness to network metric updates, and reduce unnecessary overhead in DAO transmissions. The result is more reliable network connectivity, faster recovery from topology changes, and better overall network performance.

  • Improved DIS transmission strategy to avoid overloading devices in crowded networks, reducing congestion during connection phases in dense networks.

  • Border Router now rejects DAO routes that would create source routing loops, improving the availability of downstream routes.

  • Border Router now removes associated EARO routes when receiving a DAO without itself in the transit list.

  • Accept tunneled IPv6 packets without any RPL hop-by-hop option or Source Routing Header (SRH).

  • Removed the RSL threshold applied over radio sensitivity that prevented accepting in-range RPL candidates, increasing the range.

• LFN Improvements

  • Added support for multicast packets originated by LFNs.

  • Improved the reliability of transmissions towards LFNs.

  • Prioritize LFN transmission on FFN broadcast dwell interval when they overlap.

  • LFNs now maintain TID across power cyclings.

  • Improved LFN LPCS retry policy.

  • Reject unsupported FFN-managed LFN Window Style.

  • Added handling of LTO-IE with 0 ms Adjusted Listening Interval.

  • Added the LFN listen interval that was missing in the Neighbor Report Information Element (NR-IE).

  • Always insert an IPv6 tunnel header when routing to a LFN parent.

  • Improved LFN parenting features and dropped LFN_PAN_TIMEOUT.

• MAC and PHY

  • Enhanced MAC security neighbor table management to prevent instabilities that occurred when the table reached capacity.

  • Optimized MAC retry strategy for improved transmission reliability.

  • Reduced delay before transmission, improving the maximum throughput.

  • Improved POM-IE (PHY Operating Mode Information Element) handling by removing the element when no PHY support is declared via sl_wisun_set_pom_ie().

• Security

  • Improved protection against key reinstallation.

  • Improved handling of frame counter rollover.

• Border Router

  • Added DODAG version number and DTSN to the SoC BR's NVM. Added a DTSN increase in case of unexpected SoC BR's reboot.

  • Made the border router send a PCS on reboot to retrieve the broadcast timings quicker.

• Network Management

  • Reduced the amount of unnecessary address registration.

  • Replaced NS-ARO zero lifetime with a 60s lifetime.

  • Removed Random Early Detection (RED) congestion algorithm. It is not part of the Wi-SUN specification, performs poorly in heterogeneous environments, and has shown no substantial benefit in homogeneous environments.

  • Optimized default timer configuration values for authentication procedures, improving initial connection reliability and speed.

• Code Size

  "Release" libraries are now LTO-enabled.

• Configuration and Initialization

  Removed explicit PTI enable from Wi-SUN stack initialization. The default state can be set in sl_rail_util_pti configuration.

Removed Features#

None.

Deprecated Features#

None.

API Changes#

New APIs | Modified APIs | Removed APIs | Deprecated APIs

New APIs#

Added in 2.11.0#

None.

Added in 2.10.0#

Modified APIs#

Modified in 2.11.0#

Modified in 2.10.0#

None.

Removed APIs#

None.

Deprecated APIs#

Deprecated in 2.11.0#

None.

Deprecated in 2.10.0#

Deprecated in 2.6.0#

Bug Fixes#

Fixed in 2.11.0#

Fixed in 2.10.0#

Chip Enablement#

None.

Application Example Changes#

New Examples | Modified Examples | Removed Examples | Deprecated Examples

New Examples#

Added in 2.11.0#

None.

Added in 2.10.0#

Modified Examples#

Modified in 2.11.0#

Modified in 2.10.0#

Removed Examples#

None.

Deprecated Examples#

None.

Known Issues and Limitations#

Impact of Release Changes#

Impact Statements | Migration Guide

Impact Statements#

None.

Migration Guide#

• The 2025.12 version of the Silicon Labs Radio Configurator does not support the exact same set of radio configurations as previous releases. As a result, you may need to update your radio configuration before the application can be generated. If the radio configuration fails to build, you can resolve the issue by following one of these approaches:

  • Recreate the application from scratch. Recommended if you are using an unmodified sample application.

  • Remove the failing PHY entry from the radio configuration. Recommended if the problematic PHY is not used by your application.

  • Remove the failing PHY entry and then add the updated version of that PHY. Recommended if neither of the above solutions applies.

• From Simplicity Studio 6, right click on "radio_settings.radioconf" then select "Open in File Explorer". Open the file with a text editor and remove the base_channel_configuration section that contains the PHY entry reported to be failing to generate.

• Previous versions of "Wi-SUN - LFN CLI" were using SL_POWER_MANAGER_EVENT_TRANSITION_ENTERING_EM3 that was removed in that version 2025.6 of the Simplicity SDK. Applications generated with an older release of the Simplicity SDK will not compile against version 2025.6. All references to SL_POWER_MANAGER_EVENT_TRANSITION_ENTERING_EM3 can be safely deleted.

Using This Release#

What's in the Release?#

This release contains the following:

• Wi-SUN stack library

• Wi-SUN sample applications

• Wi-SUN border router and RCP pre-compiled demos

• Documentation

If you are a first-time user, see the Wi-SUN Getting Started Guide.

Compatible Software#

Installation and Use#

The Wi-SUN SDK is distributed as part of the Simplicity SDK, Silicon Labs' unified software development kit suite. To get started quickly, install Simplicity Studio 6, which provides a complete development environment, including project and resource management, software configuration tools, a full IDE with GNU toolchain, and analysis utilities. Step-by-step installation instructions are available in the Simplicity Studio 6 User’s Guide.

Documentation for each SDK version is included with the SDK installation.

For information about Secure Vault Integration, see Secure Vault.

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SDK Release and Maintenance Policy#

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