Simplicity SDK Version 2026.6.0 - Release Notes (Jun 23, 2026)#

Platform

6.1.0

Jun 23, 2026

Platform MCU

• Debug Logger: Logger support added (evaluation quality).
• Watchdog Manager: Watchdog manager support added (evaluation quality).
• sl_main: Added a new app_init_post_platform application hook in sl_main_second_stage_init, called after sl_platform_init, sl_driver_init, and sl_service_init complete and before sl_stack_init. This hook lets applications run initialization that depends on platform components, drivers, and services but must run before stacks are initialized.
• Linker: Added support for RAM-only execution for provisioning applications (GCC toolchain).
• Startup code: Added an assembly reset handler trampoline so safe code can execute before the C environment is loaded.

Security

• Added support for NIST SP 800-108r1 key derivation, enabling PUF-based key derivation on xG27 devices
• Added new fine-grained SLC components for Mbed TLS X509, PK, SSL, and DTLS client/server APIs to reduce code size for specific use cases.

Bootloader

• Added support for the BRD4419A evaluation board.
• Updated the default Series 3 bootloader clock configuration to use SoCPLL at 145 MHz sourced from HFRCO.
• Added support for dynamic application image selection in dual-application bootloaders using a flash-based switch mechanism.

Micrium OS

• None

CPC

• None

MVP Math Library

• None

Platform MCU

• Added Lion Rev2 (EFR32BG29/EFR32MG29) OPN and radio board support.
• Added EFR32FG2D (Serval GA) and WPK Main Board (BRD4002B) support.

Bootloader

• Added support for the xG2B device family.

RAIL Library

3.1.0

Jun 23, 2026

• Event/config visibility
• AF sensing and multiprotocol timing support
• TX PA interface refresh with migration toward newer power-table APIs

RAIL SDK

3.1.0

Jun 23, 2026

None

None

USB

1.7.0

Jun 23, 2026

Wi-Fi 6 + BLE (WiSeConnect)

4.1.0

Jun 23, 2026

• Multicast / broadcast filtering with IP allowlist and beacon-drop threshold
• WPA3 H2E SE
• BSS Max Idle
• Debug logging v2 (SL_DEBUG_LOG_V2) and Internal Buffer Manager

Network Stack

• Added support to configure the DNS timeout from host.
• Added Embedded MQTT password length support up to 512 bytes.
• Added support for graceful TCP FIN handshake closure.
• Upgraded the lwIP stack from v2.1.2 to v2.2.1.

SiWx91x Bluetooth LE

• Added support for dynamically enabling or disabling BLE.
• Added logging support for BLE.
• Added RC clock support for BLE.
• Added support for BLE stack bypass/offloading.

Multiprotocol

• Support for concurrent two BLE connections with advertising extensions and WLAN TCP TX data transfer in NCP.
• Support for concurrent operation of eight BLE peripheral connections, two BLE central devices, and WLAN MQTT data transfer in NCP mode.

• Added a Memory Manager Redirect component to redirect libc heap allocations to the CMSIS FreeRTOS heap_4 allocator by using heap wrappers.
• Upgraded GCC to 14.2 and enabled Link Time Optimization (LTO) for GCC-based builds.
• Updated SiWx91x platform code to Support BRD4002B Mainboard with EFR Driver Integration.

SoC: BRD4343C (SiW917Y-RB4343C) radio board for refreshed SiWG917Y SoC modules with external 32 kHz LP crystal pins; module OPNs SiWN917Y100LGAXA, SiWN917Y100LGNXA, SiWG917Y110LGNXA, SiWG917Y111MGNXA, SiWG917Y121MGNXA, SiWG917Y110LGAXA, SiWG917Y111MGAXA, SiWG917Y121MGAXA.

NCP: BRD4357C (SiW917Y-RB4357C) radio board for refreshed SiWN917Y NCP modules with external 32 kHz LP crystal pins; module OPNs SiWN917Y100LGAXA, SiWN917Y100LGNXA.

New boards: BRD4343C

New chip components (SiWx917Y / SiWN917Y modules) under components/device/silabs/si91x/mcu/core/chip/component/:

• siwg917y110lgaxa, siwg917y110lgnxa
• siwg917y111mgaxa, siwg917y111mgnxa
• siwg917y121mgnxa, siwg917y121mgaxa
• siwn917y100lgaxa, siwn917y100lgnxa (NCP refresh)

OpenThread

3.1.0

Jun 23, 2026

• Added Thread 1.4 qualification support for OTBR in NCP mode.
• Continued Thread 1.4 qualification support for SoC and OTBR in RCP mode.
• Added Thread - SoC Empty sample applications.
• Added NAT64 and TREL support for Host / NCP configurations.
• OTBR support on Android 15 with CPC spinel proxy support.
• Standardized Simplicity SDK example app titles and descriptions.
• Silicon Labs standard logger integration.

Zigbee

9.1

Jun 23, 2026

• Configurable next RX channel for Green Power Device (GPD) bi-directional commissioning.
• Secure inter-PAN message fragmentation with APS link encryption after key establishment.
• Packet handoff post-incoming filter with per-packet link quality (RSSI, LQI, channel).
• Zigbee 4.0 gateway sample application.
• GCC and IAR toolchain upgrades (GCC 14.2.rel1 and IAR 9.70.4).
• Antenna calibration APIs for networking products.
• Configurable route table size in Zigbee Pro Stack Config.

Bluetooth LE

11.1.0

Jun 23, 2026

Example and Middleware

• Added Serial Port Profile middleware through the new spp component and related configuration and GATT service content.
• Added new Bluetooth peer manager and peer security middleware components for central, peripheral, filter, common, and security flows.

Host Stack

• New flag `SL_BT_PERIODIC_ADVERTISER_INCLUDE_ADVERTISING_DATA_INFORMATION` in `sl_bt_periodic_advertiser_flags` enables the inclusion of Advertising Data Information (ADI) in transmitted periodic advertising PDUs.
• New command `sl_bt_periodic_advertiser_refresh_data_id` enables refreshing the Advertising Data ID (DID) without the need to provide the same data again.
• New mode `sl_bt_sync_report_non_duplicate` in `sl_bt_sync_reporting_mode_t` enables filtering duplicate periodic advertisements.
• The `bluetooth_feature_linklayer_interface` component provides new commands `sl_bt_linklayer_get_hci_connection_handle` and `sl_bt_linklayer_get_bgapi_connection_handle` for converting between link layer HCI connection handles and the BGAPI host stack connection handles. The application needs to convert between handle types when it uses the linklayer class to access low-level link layer functionality that uses connection handles.
• The bluetooth_feature_connection_analyzer feature can now maintain synchronization to the analyzed connection even if connection parameters or channel map is updated. The LLCP events need to be passed from the Central device to the connection analyzer device by the application. Use the `bluetooth_feature_connection_analyzer_llcp_report` component and the `sl_bt_linklayer_event_info_reporting_enable` command to enable the LLCP reporting on the Central. Pass the corresponding LLCP events from `sl_bt_evt_linklayer_event_info_report` events to the connection analyzer device and use `sl_bt_connection_analyzer_process_llcp_event` to process the event.
• New command `sl_bt_gap_set_privacy_mode_with_rpa_randomization` enables configuring local privacy with separate minimum and maximum RPA rotation intervals. When the interval bounds differ, advertiser and central-side RPAs are refreshed at randomized times within the configured range. Keeping the interval bounds equal preserves deterministic rotation behavior.
• New events `sl_bt_evt_gap_random_address_refresh` and `sl_bt_evt_advertiser_random_address_refresh` notify the application when the scanner/initiator or a stack-managed advertiser starts using a new private address. The related privacy mode commands document these events.
• New command `sl_bt_resolving_list_read_peer_resolvable_address` reads the current peer resolvable private address tracked by the controller for a device in the Resolving List.
• The `bluetooth_feature_cs` component adds Channel Sounding (CS) handover commands and events to the cs BGAPI class. Use the `bluetooth_feature_cs_handover_leader` and `bluetooth_feature_cs_handover_follower` components to enable the corresponding controller-side handover roles. Retrieve CS procedure parameters from the CS Leader, pass them to the CS Follower, and use the handover commands and events to synchronize the Follower to the CS procedure and LE connection and to control scheduled CS procedure execution.

Controller

• Added support for ADI in Periodic Advertising and Periodic Advertising with Responses, improving interoperability with devices expecting this capability.
• Added Channel Map Update Indication support for the Periodic Advertising advertiser, enabling Adaptive Frequency Hopping with Periodic Advertising for improved reliability in congested or noisy RF environments.

Multiprotocol

CMP + BLE-RCP sample applications (Zigbee NCP + OpenThread RCP + Bluetooth RCP)

• Added new Concurrent Multiprotocol (CMP) co-processor sample projects that run Zigbee NCP, OpenThread RCP, and Bluetooth RCP on one EFR device. The Bluetooth side exposes a BLE controller over CPC so a Linux host can use the Silicon Labs RCP with CPCd and a standard Bluetooth stack (i.e. BlueZ). Zigbee and OpenThread host applications use the same CPC multiplexer model as existing NCP / RCP designs.

Multiprotocol

xG2B: Added Alpha software support for xG2B devices in Multiprotocol.

Bluetooth Mesh

11.0.0

Jun 23, 2026

• GCC and IAR compiler version updates

Bluetooth Location Services

11.0.0

Jun 23, 2026

Real-Time Locationing Service

The RTL Service (`rtl_service`) is a new software component providing a unified API that works in both RTOS and bare-metal environments.

• The service automatically adapts: in RTOS mode it runs a dedicated processing task; in bare-metal mode it processes within the application main-loop.
• All API functions can be called from any task or interrupt context. The service handles mutual exclusion internally.
• Submit CS or Ranging Service (RAS) procedure data and receive distance estimates asynchronously through a result callback.

RTL Library Version Function

• A function `sl_rtl_get_lib_version()` was added to return the exact library version.

Algorithm Mode Enum Renaming

The enum `sl_rtl_cs_algo_mode` field names have been renamed as follows:

• `SL_RTL_CS_ALGO_MODE_REAL_TIME_BASIC` renamed to `SL_RTL_CS_ALGO_MODE_TRACKING_ACCURACY_OPTIMIZED`
• `SL_RTL_CS_ALGO_MODE_REAL_TIME_FAST` renamed to `SL_RTL_CS_ALGO_MODE_TRACKING_LATENCY_OPTIMIZED
• `SL_RTL_CS_ALGO_MODE_STATIC_HIGH_ACCURACY` renamed to `SL_RTL_CS_ALGO_MODE_STATIONARY`

Z-Wave

8.1.0

Jun 23, 2026

• The Silicon Labs Bootloader now supports switching multiprotocol solutions. See the [**Creating Z-Wave-BLE SMP solution**](https://docs.silabs.com/z-wave/latest/zwave-examples-smp/) instruction for an example how to build a switched multiprotocol (SMP) firmware which combines a Z-Wave Switch On/Off application and a Bluetooth OTA DFU application that can upgrade the Z-Wave app
• Added an API to customize the DTPA noise margin from the application.

  Note: The noise margin is not stored in NVM. Applications must set the customized value after each initialization.

• Added component `zw_host_hibernation` to support hibernating host controller.
• Added component `zw_cc_wakeoncriticalmessage` to support alpha command class Wake On Critical Message.
• Supported new variant of Pro Kit Mainboard: BRD4002B. The new SHT40 sensor and the previous sensor are supported by a unidriver component for dynamic run-time selection in the sample applications. Note that it causes a RAM usage increase. To avoid increased RAM usage in production, use a dedicated driver for the sensors.

Wi-SUN

2.12.0

Jun 23, 2026

• Added automatic connection parameter selection based on PAN size, with adaptation as the network grows or shrinks.
• Introduced an optional separate heap component for critical Wi-SUN stack and cryptographic allocations.
• Added Direct Connect client support with scanning, complementing the existing server role.
• Added First Breath mode for expedited upstream application data after a network outage.
• Added Last Gasp mode for a final burst of traffic before power loss.
• Expanded RF test component with dedicated TX and RX modes for production testing.

Silicon Labs Matter

2.9.0-1.5

Coming soon

Amazon Sidewalk

2.9.0

Jun 23, 2026

• Cloud Light SoC Sample application.
• Supporting new Temperature sensor on WPK board.
• Application tab enablement in Sidewalk Assistant.
• Updated libraries to Amazon Stack 1.19.4.
• Stability improvements.

Connect

4.3.0

Jun 23, 2026

Transition to Common Manufacturing Tokens instead of Legacy Token handling

EFR32FG2D

Machine Learning

3.0.0

Jun 23, 2026

• New DX for adding ML Models to new or existing projects.
• New APIs to initialize, execute, and de-initialize ML models.
• Project upgrades require manual effort. See the AI-assisted migration prompt.
• Multiple-Model feature to add and execute multiple ML models in a project.

Simplicity Connect Mobile App

3.3.0

Jun 23, 2026

• Added Simplicity Connect rebranding.
• Added Matter demos for Oven and Range Hood.
• Added example app titles to the app and user guide.
• Added a proximity lock demo via channel sounding on Android.