Azure RTOS transition to open-source is now complete

This post has been republished via RSS; it originally appeared at: New blog articles in Microsoft Community Hub.

Following up on my blog post from November 2023 announcing the transition of Azure RTOS to open-source, today I am excited to announce that the contribution of Azure RTOS to the Eclipse Foundation is now complete.  The Eclipse ThreadX 6.4.1 release is now available and the Eclipse ThreadX open-source project is now fully under the stewardship of the Eclipse Foundation.   See more at


This first release of the ThreadX real-time operating system (formerly Azure RTOS) and middleware components under MIT license is functionally equivalent to Azure RTOS 6.4, the exact same great product that has already been deployed on billions of embedded systems worldwide.



(Image provided courtesy of Eclipse Foundation under CC-BY-SA International license)



Broadening access and use cases

Eclipse ThreadX 6.4.1 is a major milestone for the open-source community, as it marks the transition of Azure RTOS from a proprietary license to a permissive one. The MIT license allows anyone to use, modify, and distribute the RTOS and its source code without any restrictions. This means that developers can now leverage the power and reliability of Eclipse ThreadX for any project, whether it is commercial, academic, or personal.  Additionally, all the previous 6.x versions of Azure RTOS are also available under the MIT license, giving developers the flexibility to choose the version that best suits their needs and migrate to the latest one at their own pace. T


Another important feature of this release is that the Eclipse ThreadX middleware components, also released under the MIT license, such as FileX, GUIX, NetX Duo, and USBX, can now be used independent of the RTOS. This means developers can use these components with other real-time operating systems or even without an RTOS. Example use cases include using GUIX with Zephyr RTOS, or using USBX on a bare metal system, etc.


The previous 6.x versions and middleware components can be found in the release section of the GitHub repositories under the Eclipse ThreadX organization at


Pre-certified for safety-critical use cases

We are also including the safety certified versions of ThreadX and middleware components in the releases under the MIT license. These versions have been previously certified by TÜV and UL, leading certification bodies, for use in safety-critical applications, such as medical, automotive, and industrial devices. Specifically, the safety-certified versions are:





ThreadX SMP




NetX Duo





Access to safety certification artifacts going forward will be managed by the Eclipse Foundation. Details on that will be announced soon. To stay informed on future updates, please join the Eclipse ThreadX mailing list at



We are super excited to see what the embedded developer community will be building with Eclipse ThreadX 6.4.1 and its middleware components in new projects going forward. We welcome your feedback and contributions to the project, as we aim to grow the open-source community and ecosystem around Eclipse ThreadX.


You can find more information about the project, the documentation, and the support channels on the Eclipse ThreadX website or send inquiries to

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