Back in 2019, Microsoft acquired Express Logic, a leader in real time operating systems (RTOS) for IoT and edge devices powered by microcontroller units (MCUs). During the time of acquisition, ThreadX RTOS had over 6.2 billion deployments, making it one of the most deployed RTOS. Following the acquisition, Microsoft rebranded ThreadX RTOS as Azure RTOS. By 2023, RTOS had more than 12 billion deployments worldwide.

In November last year, Microsoft announced that it will open-source Azure RTOS. As part of this process, Microsoft announced that Azure RTOS will be transitioning to an open-source model under the stewardship of the Eclipse Foundation, a recognized leader in hosting open-source IoT projects.

Today, Microsoft announced that Azure RTOS transition to Eclipse Foundation is now complete. Azure RTOS is now called as Eclipse ThreadX. Eclipse ThreadX now offers a vendor-neutral, open source, safety certified OS for real-time applications, all under a permissive MIT license. The MIT license will enable any organization to use, modify, and distribute the RTOS and its source code without any restrictions. The first open source Eclipse ThreadX 6.4.1 release is now available.

In addition to the Eclipse ThreadX RTOS, the middleware components are also available under open-source MIT license. You can find them below.

To help developers, Microsoft is also releasing all the previous 6.x versions of Azure RTOS under the MIT license. This move to open source under the Eclipse Foundation promises exciting developments for the future of Eclipse ThreadX and the IoT industry.