Simplicity SDK Version 2025.12.3 - Release Notes (May 4, 2026)#

The primary tool for the Silicon Labs IoT software development ecosystem, combining wireless software development kits (SDKs) and platform into a single, integrated package.

Release Announcement#

Starting with the 2025.12 release, the Simplicity SDK transitions from GitHub-based monolithic delivery to a modular, Conan-based package model.

To obtain and work with the Simplicity SDK 2025.12, customers must use Silicon Labs Tool (SLT) v1.1.0 or newer, available through:

  • SLT-CLI (v1.1.0+) – a standalone command-line tool

  • Simplicity Installer (v1.1.0+) – a graphical installer that integrates SLT-CLI functionality

This update also introduces a new directory structure organized by technology and functional domain, which may affect how SDKs are integrated, consumed, and automated in developer workflows.

Developer Guidance#

CLI development (Headless or CI/CD dev setups)#

  • Need to update scripts that rely on ‘git clone’ and integrate SLT to manage and automate the SDK delivery.

  • Any tooling, scripts, or manual workflows that rely on fixed SDK paths may need to be updated accordingly.

GUI development (Simplicity Studio 6)#

  • No SLT-CLI integration is needed, but note that SDKs are now stored in versioned Conan package directories managed by SLT.

  • Directory path changes:

    • Studio 5 (SDK 2025.6): ~/SimplicityStudio/SDKs/simplicity_sdk

    • Studio 6 (SDK 2025.12): ~/.silabs/slt/installs/conan/p/simplxxxxxxxxxxx/p

Resources#

Note: This Simplicity SDK release will be published on GitHub for reference purposes only, not recommended for development. Development should use the SDK packages delivered via SLT.

Release Summary#

Release Item Version Release Date Key Features Chip Enablement

Platform

6.0.2

May 4, 2026

 Platform MCU
  • Automatic PCLK divider selection defaults to datasheet-compliant values.
  • Power Manager adds EM0/EM1 voltage scaling and power savings.
  • Expanded Clock Manager validation and oscillator configuration options.
Bootloader
  • Added EM4 GPIO retention during Firmware Upgrade feature for Series-2 devices.
  • Added support for the xG2D device family.
Security
  • Added support for the Key Storage Unit (KSU) in the PSA Crypto API.
Micrium OS
  • Restricted Micrium OS usage to Series 2 devices.
CPC
  • Soft reset capability for future usage.
  • SPI driver maintenance: removed legacy MMLDMA workaround.
MVP Math Library
  • None
  • EFR32FG23L010F128GM40
  • EFR32FG23L020F128GM40

RAIL Library

3.0.3

May 4, 2026

 Targeted quality improvements and bug fixes. Added support for the xG2D device family.

RAIL SDK

3.0.2

May 4, 2026
  • Added RAIL 3.0.0 Library support.
  • Added IEEE 802.15.4 BPSK protocol support.
 No new chips enabled this release.

USB

1.6.0

Jan 22, 2026

 Underlying platform changes only. No new chips enabled this release.

Wi-Fi 6 + BLE (WiSeConnect)

4.0.2

May 4, 2026

 Wi-Fi
  • Added Wi-Fi Protected Setup (WPS) Push Button Configuration (PBC) feature support in Station mode.
  • Vendor-specific IE support for Station (STA), SoftAP, and Concurrent Modes.
Network Stack
  • Added DHCP support from host for IPv4 in Dual Stack mode.
  • Added SNI extension support for Embedded MQTT.
  • Added NAT/PAT feature support.
  • Added DNS IP address support in AP mode.
  • Added support for Subject Name validation during TLS connections.
  • Added IPv6 support in Dual Stack mode.
  • Added DNS-SD support over mDNS for IPv4 and IPv6.
  • Added adaptive timer optimizations in hosted Network Stack LWIP (IPv6 ND6, DHCP, DNS, ARP, ACD, TCP, and MLD6) for improved power efficiency.
SiWx91x Platform
  • Introduced Wakeup-on-Wireless feature.
  • Enhanced driver support for BOD, OPAMP and SSI Peripherals.
  • Added CMake build system support.
 No new chips enabled this release.

OpenThread

3.0.2

May 4, 2026

 OpenThread
  • Continued compliance for Thread 1.4 on SoC and OTBR.
  • OpenThread Border Router in NCP mode with Thread 1.3 feature support.
  • Multi-PAN support for Thread in SoC mode.
Multiprotocol
  • Concurrent Listening support with CMP on SiMG301x.
  • Bi-directional Green Power support with CMP Zigbee NCP + OpenThread RCP.
 OpenThread
  • None.
Multiprotocol
  • xGM270S Leopard SiP Module GA SW support.
  • xG301 Explorer Kit and Pro-kit support.

Zigbee

9.0 Revision 2

May 4, 2026

 Zigbee
  • Zigbee 4.0 compliance with BDB 3.1 and R23 support.
  • Dynamic switching of Zigbee node type between router and sleepy end device.
  • Inter-PAN messages filtering update.
  • Software support for new Series 3 boards.
  • Dynamic Hardware Configuration (DHC) for host/NCP PA calibration.
  • Series 3 SPI NCP build fixes and supported SPI NCP applications with documented host/NCP pin alignment (known limitation: intermittent Gateway start on SPI NCP).
  • Simplicity Studio: Zigbee 4.0 Security selectable for Primary and Secondary Network Security Type under Zigbee Device Config (including Z3Gateway projects).
  • End Device Support component: configurable move delay via SL_ZIGBEE_AF_PLUGIN_END_DEVICE_SUPPORT_MOVE_DELAY_SECONDS.
Multiprotocol
  • Concurrent Listening support with CMP on SiMG301x.
  • Bi-directional Green Power support with CMP Zigbee NCP + OpenThread RCP.
 Zigbee
  • All Variants.
  • Series 3 SPI NCP enabled when host and NCP SPI pin maps are configured compatibly (see SPI NCP Configuration and hardware documentation).
Multiprotocol
  • xGM270S Leopard SiP Module GA SW support.
  • xG301 Explorer Kit and Pro-kit support.

Bluetooth LE

11.0.2

May 4, 2026

 Example and Middleware
  • Host examples shown on Studio Launcher page.
  • Most bootloader-aware example applications converted to standalone to simplify early development.
Host Stack
  • Bluetooth host qualification for Core specification 6.1.
  • PAwR event counter reporting.
  • Channel classification reporting for a remote peripheral device.
  • Support for larger BGAPI payload size in NCP applications.
Controller
  • PAwR event counter reporting.
  • Support for HCI_LE_Set_Resolvable_Private_Address_Timeout (v2).
Multiprotocol
  • Concurrent Listening support with CMP on SiMG301x.
  • Bi-directional Green Power support with CMP Zigbee NCP + OpenThread RCP.
 Bluetooth LE
  • Added xGM270S SiP module support.
Multiprotocol
  • xGM270S Leopard SiP Module GA SW support.
  • xG301 Explorer Kit and Pro-kit support.

Bluetooth Mesh

10.2.0

May 4, 2026

 Targeted quality improvements and bug fixes. No new chips enabled this release.

Bluetooth Location Services

11.0.2

May 4, 2026
  • Support for multiple sub-events per initiator and reflector role in a CS procedure.
  • Support for non-zero maximum procedure count in REAL_TIME_FAST algorithm mode.
 No new chips enabled this release.

Z-Wave

8.0.2

May 4, 2026
  • Addressing the increasing demands for low power in battery-operated devices, the Z-Wave stack is now implemented independently from the platform power state (e.g., energy modes: EM0, EM1, EM1P, EM2, EM3/EM4).
  • The Z-Wave Long Range TX output power algorithm is refactored.
  • The 9.6 kbps PHY is used only if an end device in the network is not able to operate at a higher modulation rate (40 kbps or 100 kbps).
 No new chips enabled this release.

Wi-SUN

2.11.1

May 4, 2026
  • Significant RPL performance improvements and enhanced network stability.
  • Enhanced LFN support.
  • Release of Wi-SUN NCP (Network Co-Processor) application for evaluation purposes.
  • New border router sample applications.
  • Significant memory footprint reduction.
  • FAN 1.0 certification support.
 No new chips enabled this release.

Silicon Labs Matter

2.8.1-1.5

Mar 25, 2026
  • Quality-tested Matter 1.5 solution for Thread and WiFi.
  • Added support for Amazon Matter Simple Setup (MSS) with 917SoC.
  • Added Matter demo for an Oven and Range Hood App.
  • Added further optimizations in LwIP timers.
 This release supports Series 2 and Series 3 EFR32 devices. Use v2.2.x-1.2 for Series 1 devices.

Amazon Sidewalk

2.8.2

May 4, 2026
  • Support for RAIL 3.0.
  • Support for Simplicity SDK 2025.12.3.
 No new chips enabled this release.

Connect

4.2.2

May 4, 2026

 Added RAIL 3.0.0. integration in both Stack and SDK. No new chips enabled this release.

Machine Learning

2.2.2

May 4, 2026
  • New ML Model Profiler is available in 2 formats, ML Model Profiler Tool and ML Model Profiler Component.
  • New sample applications are available for Profiling ML Models, Data Capture from IMU, and Device Tampering Detection.
  • EFR32MG24B310F1536IM48
  • EFR32MG24B210F1536IM48
  • EFR32MG24B220F1536IM48
  • EFR32MG26B510F3200IM68
  • EFR32MG26B410F3200IM48
  • EFR32MG26B420F3200IM48
  • EFR32MG26B510F3200IL136
  • EFR32MG26B410F3200IM68
  • EFR32MG26B420F3200IM68
  • EFR32MG26B510F3200IM48
  • EFR32ZG28B312F1024IM48
  • EFR32ZG28B312F1024IM68
  • EFR32ZG28B322F1024IM68
  • EFR32ZG28B312F1024IM68
  • SiWG917M111MGTBA
  • SiWG917M141XGTBA
  • SiWG917Y111MGNBA
  • SiWG917Y111MGAB4
  • SiWG917Y121MGNB4

Simplicity Connect Mobile App

3.2.2

May 4, 2026

None

 No new chips enabled this release.

Note: Click here for earlier releases on GitHub.

Looking for older release notes? You can still access previous versions for both Simplicity SDK (prior to 2025.6.0) and Gecko SDK here.