Our newest embedded software platform, the Simplicity Software Development Kit (SDK), is designed specifically for our Series 2 and upcoming Series 3 devices. The Simplicity SDK is a significant advancement in IoT development, providing our customers with a cohesive development environment for wireless innovation. It enables wireless developers to utilize advanced features and capabilities with the most recent Silicon Labs IoT devices.
Meanwhile, our Gecko Software Development Kit (GSDK) will continue to be available for users of our Series 0 and Series 1 devices.??
The Gecko SDK will continue to support all Series 0 and 1 devices with no change to the long-term support, maintenance, quality, and responsiveness provided under our software policy.The new SDK will branch from Gecko SDK and begin to offer new features that help developers take advantage of the advanced capabilities of our Series 2 and 3 products.
This decision aligns with customer feedback, reflecting our commitment to elevate quality, ensure stability, and enhance performance for an exceptional user experience across our software SDKs.
Which SDK Do I Need?
Separate SDKs for Series 0 & 1 and Series 2 & 3 Starting in Q2 2024.
Have a question about which Series you're using. Learn more using our Series Directory.
For information about our support and maintenance visit our?SDK Release and Maintenance Policy?page.
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Simplicity SDK
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Gecko SDK
Simplicity SDK Release Notes (2025.6.1)
Latest Release - Q2/2025 ?(July 2025)
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View Latest Versions of All SiSDK Release Notes Here
Platform Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest | View Latest Version? |
| 2025/08 | Version 5.1.3.0? |
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| 2025/04 | Version 5.0.3.0? |
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| 2025/04 | Version 5.1.2.0? |
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| 2025/02 | Version 5.1.1.0? |
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| 2024 | 2024/12 | Version 5.1.0.0? |
| 2024/09 | Version 5.0.2.0? |
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| 2024/07 | Version 5.0.1.0? |
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| 2024/06 | Version 5.0.0.0? |
Bluetooth LE Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 9.1.1.0? |
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| 2025/04 | Version 8.3.0.0? |
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| 2025/04 | Version 9.1.0.0? |
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| 2025/02 | Version 9.0.1.0? |
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| 2024 | 2024/12 | Version 9.0.0.0? |
| 2024/09 | Version 8.2.0.0? |
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| 2024/07 | Version 8.1.0.0? |
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| 2024/06 | Version 8.0.0.0? |
Bluetooth Location Services Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 9.1.0.0? |
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| 2025/04 | Version 8.3.0.0? |
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| 2025/04 | Version 9.1.0.0? |
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| 2024 | 2024/12 | Version 9.0.0.0? |
| 2024/09 | Version 8.2.0.0? |
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| 2024/07 | Version 8.1.0.0? |
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| 2024/06 | Version 8.0.0.0? |
Bluetooth Mesh Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 8.1.0.0? |
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| 2025/04 | Version 7.0.3.0? |
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| 2025/04 | Version 8.0.2.0? |
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| 2025/02 | Version 8.0.1.0? |
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| 2024 | 2024/12 | Version 8.0.0.0? |
| 2024/09 | Version 7.0.2.0? |
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| 2024/07 | Version 7.0.1.0? |
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| 2024/06 | Version 7.0.0.0? |
Bluetooth Mesh ADK Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 8.1.0.0? |
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| 2025/04 | Version 7.0.3.0? |
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| 2025/04 | Version 8.0.2.0? |
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| 2025/02 | Version 8.0.1.0? |
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| 2024 | 2024/12 | Version 8.0.0.0? |
| 2024/09 | Version 7.0.2.0? |
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| 2024/07 | Version 7.0.1.0? |
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| 2024/06 | Version 7.0.0.0? |
Connect SDK Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 4.0.3.0? |
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| 2025/04 | Version 4.0.2.0? |
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| 2025/02 | Version 4.0.1.0? |
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| ?2024 | 2024/12 | Version 4.0.0.0? |
OpenThread Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latst Version? |
| 2025/08 | Version 2.6.3.0? |
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| 2025/04 | Version 2.5.3.0? |
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| 2025/04 | Version 2.6.2.0? |
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| 2025/02 | Version 2.6.1.0? |
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| 2024 | 2024/12 | Version 2.6.0.0? |
| 2024/09 | Version 2.5.2.0? |
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| 2024/07 | Version 2.5.1.0? |
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| 2024/06 | Version 2.5.0.0? |
RAIL SDK Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 2.18.3.0? |
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| 2025/04 | Version 2.18.2.0? |
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| 2025/02 | Version 2.18.1.0? |
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| ?2024 | 2024/12 | Version 2.18.0.0? |
USB Device Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/02 | Version 1.4.1.0? |
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| 2024 | 2024/12 | Version 1.4.0.0? |
| 2024/07 | Version 1.3.1.0? |
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| 2024/06 | Version 1.3.0.0? |
Wi-SUN Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 2.5.1.0? |
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| 2025/04 | Version 2.2.1.0? |
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| 2025/04 | Version 2.5.0.0? |
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| 2025/02 | Version 2.4.0.0? |
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| 2024 | 2024/12 | Version 2.3.0.0? |
| 2024/09 | Version 2.2.0.0? |
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| 2024/07 | Version 2.1.0.0? |
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| 2024/06 | Version 2.0.0.0? |
Zigbee EmberZNet Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 8.1.3.0? |
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| 2025/04 | Version 8.0.3.0? |
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| 2025/04 | Version 8.1.2.0? |
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| 2025/02 | Version 8.1.1.0? |
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| 2024 | 2024/12 | Version 8.1.0.0? |
| 2024/09 | Version 8.0.2.0? |
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| 2024/07 | Version 8.0.1.0? |
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| 2024/06 | Version 8.0.0.0? |
Z-Wave and Z-Wave Long Range 800 Release Notes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | Latest Version | View Latest Version? |
| 2025/08 | Version 7.23.4.0? |
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| 2025/04 | Version 7.22.4.0? |
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| 2025/04 | Version 7.23.2.0? |
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| 2025/02 | Version 7.23.1.0? |
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| 2024 | 2024/12 | Version 7.23.0.0? |
| 2024/09 | Version 7.22.2.0? |
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| 2024/07 | Version 7.22.1.0? |
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| 2024/06 | Version 7.22.0.0 |
Gecko SDK Release Notes (4.4.6.0)
Latest Release - Q1/2025 ?(February 2025)
Gecko Platform Version 4.4.6.0
Peripherals
- New API names introduced for low-level drivers (with compatibility layer for old names)
Services
- APIs for accessing value of tokens added to Token Manager
CPC
- NVM3 module, enabling Host access to Secondary device's non-volatile memory, released at production quality
- CPC Primary, for use with MCU Hosts, released at Experimental quality
- Numerous optimizations and performance improvements made
Security
- Mbed TLS upgraded (to version 3.5.0)
RAIL
- Several new features added for EFR32xG25 devices, including a new component for selecting modulations supported by the software modem
- Support added for several new PHYs, including Sidewalk PHYs on EFR32xG23 and EFR32xG28
Other Components
- Compilers upgraded (to GCC 12.2.1 and IAR 9.40.1)?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 4.4.6.0? |
| 2025/01 | Version 4.2.7.0? |
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| 2024? | 2024/10 | Version 4.4.5.0? |
| 2024/08 | Version 4.4.4.0? |
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| 2024/07 | Version 4.2.6.0? |
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| 2024/05 | Version 4.4.3.0? |
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| 2024/04 | Version 4.4.2.0? |
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| 2024/03 | Version 4.3.3.0? |
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| 2024/02 | Version 4.4.1.0? |
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| 2024/01 | Version 4.2.5.0? |
32-bit MCU Version 6.6.6.0
- Added support for new OPNs
- Upgrade compilers to GCC 12.2.1 and IAR 9.40.1?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 6.6.6.0? |
| 2025/01 | Version 6.4.7.0? |
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| 2024 | 2024/10 | Version 6.6.5.0? |
| 2024/08 | Version 6.6.4.0? |
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| 2024/07 | Version 6.4.6.0? |
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| 2024/05 | Version 6.6.3.0? |
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| 2024/04 | Version 6.6.2.0? |
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| 2024/03 | Version 6.5.3.0? |
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| 2024/02 | Version 6.6.1.0? |
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| 2024/01 | Version 6.4.5.0? |
Bluetooth Version 7.3.0.0
- Bluetooth
- New feature component bluetooth_feature_connection_analyzer provides the functionality to capture and analyze the RSSI of transmissions on a Bluetooth connection
- New feature component bluetooth_feature_connection_analyzer provides the functionality to capture and analyze the RSSI of transmissions on a Bluetooth connection
- Multiprotocol
- Concurrent Listening support (RCP) – MG21 and MG24
- Concurrent Multiprotocol (CMP) Zigbee NCP + OpenThread RCP – production quality
- Dynamic Multiprotocol Bluetooth + Concurrent Multiprotocol (CMP) Zigbee and OpenThread support on SoC
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| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.3.0.0? |
| 2025/01 | Version 5.2.0.0? |
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| ?2024 | 2024/10 | Version 7.2.0.0? |
| 2024/08 | Version 7.1.2.0? |
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| 2024/07 | Version 5.1.4.1? |
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| 2024/05 | Version 7.1.1.0? |
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| 2024/04 | Version 7.1.0.0? |
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| 2024/03 | Version 6.3.0.0? |
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| 2024/02 | Version 7.0.1.0? |
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| 2024/01 | Version 5.1.4.0? |
Bluetooth Location Services Version 7.3.0.0
- Underlying platform changes only
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.3.0.0? |
| 2025/01 | Version 5.2.0.0? |
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| ?2024 | 2024/10 | Version 7.2.0.0? |
| 2024/08 | Version 7.1.2.0? |
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| 2024/07 | Version 5.1.4.1? |
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| 2024/05 | Version 7.1.1.0? |
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| 2024/04 | Version 7.1.0.0? |
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| 2024/03 | Version 6.3.0.0? |
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| 2024/02 | Version 7.0.1.0? |
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| 2024/01 | Version 5.1.4.0? |
Bluetooth Mesh Version 6.1.4.0
- ?Qualified implementation of Mesh 1.1
- Added Network Lighting Control (NLC) profiles?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 6.1.4.0? |
| ?2024 | 2024/10 | Version 6.1.3.0? |
| 2024/08 | Version 6.1.2.0? |
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| 2024/07 | Version 4.2.4.0? |
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| 2024/05 | Version 6.1.1.0? |
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| 2024/04 | Version 6.1.0.0? |
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| 2024/03 | Version 5.0.3.0? |
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| 2024/02 | Version 6.0.1.0? |
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| 2024/01 | Version 4.2.3.0? |
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| 2023 | 2023/12 | Version 6.0.0.0? |
| 2023/10 | Version 5.0.2.0? |
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| 2023/08 | Version 4.2.2.0? |
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| 2023/07 | Version 5.0.1.0? |
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| 2023/06 | Version 3.0.5.0? |
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| 2023/06 | Version 5.0.0.0? |
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| 2023/05 | Version 4.2.1.0? |
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| 2023/03 | Version 4.2.0.0? |
Bluetooth Mesh ADK Version 6.0.6.0
- Added support for Networked Lighting Control (NLC) profiles. Mobile Application can detect the presence of a NLC based device and automatically provision and configure it.?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 6.0.6.0? |
| 2025/01 | Version 4.2.5.0? |
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| ?2024 | 2024/10 | Version 6.0.5.0? |
| 2024/08 | Version 6.0.4.0? |
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| 2024/07 | Version 4.2.4.0? |
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| 2024/05 | Version 6.0.3.0? |
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| 2024/04 | Version 6.0.2.0? |
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| 2024/03 | Version 5.0.3.0? |
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| 2024/02 | Version 6.0.1.0? |
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| 2024/01 | Version 4.2.3.0? |
OpenThread Version 2.4.6.0
- OpenThread
- ?Thread 1.3.0 certification compliance with Thread Test Harness v59.0 for SoC and Host-RCP architectures
- Thread 1.3.1 feature support - Experimental
- Crash Handler support
- TrustZone Evaluation support
- MR21 support for OpenThread RCP – Production?
- Multiprotocol
- Concurrent Listening support (RCP) – MG21 and MG24
- Concurrent Multiprotocol (CMP) Zigbee NCP + OpenThread RCP – production quality
- Dynamic Multiprotocol Bluetooth + Concurrent Multiprotocol (CMP) Zigbee and OpenThread support on SoC?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 2.4.6.0? |
| 2025/01 | Version 2.2.7.0? |
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| ?2024 | 2024/10 | Version 2.4.5.0? |
| 2024/08 | Version 2.4.4.0? |
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| 2024/07 | Version 2.2.6.0? |
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| 2024/05 | Version 2.4.3.0? |
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| 2024/04 | Version 2.4.2.0? |
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| 2024/03 | Version 2.3.3.0? |
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| 2024/02 | Version 2.4.1.0? |
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| 2024/01 | Version 2.2.5.0? |
Proprietary Flex Version 3.7.6.0
Rail Apps and Libraries
- ?Connect OFDM support for some applications
- EFR32xG28 Proprietary 2.4 GHz 15.4 Standard PHY support
- Added hardware support: MG24 QFN40, EFRBG22-E, EFR32xG28 Explorer Kit
Connect Apps and Stack
- SUN-FSK and SUN-OFDM support
- Long message reception and transmission
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 3.7.6.0? |
| 2025/01 | Version 3.5.7.0? |
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| 2024? | 2024/10 | Version 3.7.5.0? |
| 2024/08 | Version 3.7.4.0? |
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| 2024/07 | Version 3.5.6.0? |
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| 2024/05 | Version 3.7.3.0? |
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| 2024/04 | Version 3.7.2.0? |
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| 2024/03 | Version 3.6.3.0? |
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| 2024/02 | Version 3.7.1.0? |
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| 2024/01 | Version 3.5.5.0? |
USB Device Stack 1.2.3.0
- Targeted quality improvements and bug fixes
| Release | Date | Release Notes |
|---|---|---|
| ?2024 | 2024/08 | Version 1.2.3.0? |
| 2024/05 | Version 1.2.2.0? |
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| 2024/04 | Version 1.2.1.0? |
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| 2023 | 2023/12 | Version 1.2.0.0? |
| 2023/06 | Version 1.1.2.0? |
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| 2023/02 | Version 1.1.1.0? |
Wi-SUN Version 1.10.4.0
Wi-SUN Stack
- Added support for LFN multicast reception
- Added support for non-standard PHY configurations
- Added support for blocking sockets?
Wi-SUN Applications
- Wi-SUN – SoC Network Measurement improvements
- Wi-SUN – SoC (CoAP) Meter and Wi-SUN – SoC (CoAP) Collector improvements?
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 1.10.4.0? |
| ?2024 | 2024/10 | Version 1.10.3.0? |
| 2024/08 | Version 1.10.2.0? |
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| 2024/05 | Version 1.10.1.0? |
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| 2024/04 | Version 1.10.0.0? |
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| 2024/03 | Version 1.7.2.0? |
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| 2024/01 | Version 1.9.0.0? |
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| 2023 | 2023/12 | Version 1.8.0.0? |
| 2023/10 | Version 1.7.1.0? |
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| 2023/07 | Version 1.7.0.0? |
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| 2023/06 | Version 1.6.0.0? |
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| 2023/05 | Version 1.5.2.0? |
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| 2023/03 | Version 1.5.1.0? |
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| 2023/02 | Version 1.5.0.0? |
Zigbee EmberZNet Version 7.5.0.0
- Zigbee
- Limited support of GCC LTO
- Targeted quality improvements and bug fixes
- Limited support of GCC LTO
- Multiprotocol
- Targeted quality improvements and bug fixes
- Targeted quality improvements and bug fixes
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.5.0.0? |
| 2025/01 | Version 7.2.7.0? |
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| 2024 | 2024/10 | Version 7.4.5.0? |
| 2024/08 | Version 7.4.4.0? |
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| 2024/07 | Version 7.2.6.0? |
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| 2024/05 | Version 7.4.3.0? |
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| 2024/04 | Version 7.4.2.0? |
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| 2024/03 | Version 7.3.3.0? |
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| 2024/02 | Version 7.4.1.0? |
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| 2024/01 | Version 7.2.5.0? |
Z-Wave and Z-Wave Long Range 700/800 SDK 7.21.6.0?is certified according to the approved 2023B Specification test suite
- Targeted quality improvements and bug fixes
- Fixed an issue introduced in 7.21.4 impacting the effectiveness of a wake-up beam targeted at a FLiRS device
- For Series 800 products, it is highly recommended to move to the Simplicity SDK release stream
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.21.6.0? |
| 2025/01 | Version 7.19.8.0? |
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| 2024 | 2024/10 | Version 7.21.5.0? |
| 2024/08 | Version 7.21.4.0? |
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| 2024/05 | Version 7.21.3.0? |
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| 2024/04 | Version 7.21.2.0? |
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| 2024/03 | Version 7.20.3.0? |
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| 2024/02 | Version 7.21.1.0? |
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| 2024/01 | Version 7.19.5.0? |
Wireless SDKs
The following components are available as part of Simplicity Studio.
Explore the portfolio of Wireless IoT protocol SDKs
32-bit Microcontroller SDK
This software package provides all of the drivers and services needed for a successful 32-bit MCU project.
Bluetooth Low Energy SDK
Develop Bluetooth Low Energy wireless connectivity solutions for IoT devices and applications.
Bluetooth Mesh SDK
Develop scalable Bluetooth mesh wireless connectivity solutions for IoT devices and applications.
Flex SDK - Connect Stack
Connect is the IEEE 802.15.4 wireless networking stack. It allows you to develop proprietary connectivity applications for low-power devices quickly.
Flex SDK - RAIL
RAIL, the Radio Abstraction Interface Layer, gives you all the latest RF technologies without sacrificing the investment you’ve made in your wireless protocol.
Thread SDK - OpenThread
Here are the Thread SDK and development tools for creating IP-based 802.15.4 wireless mesh solutions.
Wi-SUN SDK
Industry-leading software stack and development tools for Wi-SUN IoT devices and applications.
Zigbee SDK - EmberZNet
Get the complete Zigbee protocol stack and all elements required for developing reliable mesh networking applications.
Z-Wave SDK
Develop Z-Wave Plus compliant IoT products quickly and cost-effectively with a complete SDK.