OpenThread Version 3.1.0 - Release Notes (Jun 23, 2026)#

The OpenThread SDK is an enhanced version of the open-source OpenThread implementation released by Google that has been tailored to work with Silicon Labs hardware.

Click here for earlier releases.

Release Summary#

Impact of Release Changes#

Impact Statements | Migration Guide

Impact Statements#

Migration Guide#

Multi-instance upgrades:

• Multi-instance applications require an app.c update only when app-level logging with instance-aware logging is enabled, in which case, implement otPlatLogOutput() and add the #include <stdint.h> and #include <openthread/instance.h> directives.

• The 25Q4 OpenThread BLE DMP samples were moved to the multiprotocol example set in 26Q2. No manual app.c changes are required for the single-instance sample. The multi-instance sample requires an app.c update only when instance-aware logging is enabled. In that case, implement otPlatLogOutput() and add the required #include <stdint.h> and #include <openthread/instance.h> directives.

Using This Release#

What's in the Release? | Compatible Software | Installation and Use | Help and Feedback

What's in the Release?#

• Silicon Labs OpenThread stack

• Silicon Labs OpenThread sample applications

• Silicon Labs OpenThread border router

Compatible Software#

Installation and Use#

The OpenThread SDK is part of the Simplicity SDK, the suite of Silicon Labs SDKs. To quickly get started with OpenThread and the Simplicity SDK, install Simplicity Studio, which will set up your development environment and walk you through Simplicity SDK installation. Simplicity Studio includes everything needed for IoT product development with Silicon Labs devices, including a resource and project launcher, software configuration tools, full IDE with GNU toolchain, and analysis tools.

Alternatively, Simplicity SDK may be installed manually by downloading or cloning the latest from GitHub. See https://github.com/SiliconLabsSoftware/sisdk-release for more information.

Documentation specific to the SDK version is installed with the SDK. API references and other information about this release are available on https://docs.silabs.com/openthread/latest/. Select your SDK version in the upper right.

For more information about the OpenThread SDK see Silicon Labs OpenThread QuickStart Guide.

If you are new to Thread see Thread Fundamentals.

To review Security and Software Advisory notifications and manage your notification preferences:

1. Go to https://community.silabs.com/.

2. Log in with your account credentials.

3. Click your profile icon in the upper-right corner of the page.

4. Select Notifications from the dropdown menu.

5. In the Notifications section, go to the My Product Notifications tab to review historical Security and Software Advisory notifications

6. To manage your preferences, use the Manage Notifications tab to customize which product updates and advisories you receive.

To learn more about the software in this release, dive into our online documentation.

Additional Information#

• OpenThread GitHub Repository

  The Silicon Labs OpenThread SDK is based on the upstream OpenThread repo (https://github.com/openthread/openthread) through ancestor commit fb274efe6. Silicon Labs' fork is available on GitHub: openthread_stack/util/third_party/openthread.

• OpenThread Border Router GitHub Repository

  The Silicon Labs OpenThread SDK is based on the upstream OpenThread Border Router repo (https://github.com/openthread/ot-br-posix) through ancestor commit 717abf0dc. Silicon Labs' fork is available on GitHub: openthread_stack/util/third_party/ot-br-posix.

• SDK Fork Patches

  Silicon Labs ships patch files that document fork changes relative to each upstream repository. See openthread_stack/README.md for the file listing, what's patched in this release, and usage instructions.

• Secure Vault Integration

  When deployed to Secure Vault High devices, sensitive keys are protected using the Secure Vault Key Management functionality. The following table shows the protected keys and their storage protection characteristics.

  Wrapped keys that are marked as “Non-Exportable” can be used but cannot be viewed or shared at runtime.

  Wrapped keys that are marked as “Exportable” can be used or shared at runtime but remain encrypted while stored in flash.

  For more information on Secure Vault Key Management functionality, see Secure Key Storage.

• Thread Certification

  This release has been qualified for Thread 1.4 compliance for the SoC and Border Router using the Thread Test Harness v64.0, the most recent Member Release available. Border Router qualification includes validation in both RCP and NCP operating modes. Silicon Labs recommends using Thread Test Harness v64.0 for all qualification efforts associated with this release. Additionally, this release includes OpenThread stack libraries that may be leveraged for certification by inheritance.

Help and Feedback#

• Contact Silicon Labs Support.

• To use our Ask AI tool to get answers, see the search field at the top of this page.

  Note: Ask AI is experimental.

• Get help from our developer community.

Feature Matrix#

Supported Features | Unsupported Features

Supported Features#

Unsupported Features#

This release includes preliminary support for selected Thread 2.0 features that have already been defined while the overall Thread 2.0 specification continues to evolve.

SDK Release and Maintenance Policy#

See our SDK Release and Maintenance Policy.