OpenThread released by Google is an open-source implementation of the Thread networking protocol
OpenThread Firmware (2023-07-06) included with Thread Test Harness V59.0 (V58.5 internal).
OpenThread Firmware for Thread 1.3 Reference (2023-01-19) included with Thread Test Harness V58.0 (V57.3+ internal).
OpenThread Firmware for Thread 1.2 Reference (2022-10-27) included with Thread Test Harness V58.0 (V57.3+ internal).
OpenThread Firmware (2020-08-18) included with Thread Test Harness V1.1 R2.2.3.
OpenThread Firmware (2019-11-13) included with Thread Test Harness V1.1 R2.0.1.
OpenThread Firmware (2018-06-19) included with Thread Test Harness V1.1 R1.4.0.
OpenThread Firmware (2018-09-26).
OpenThread Firmware (2017-07-16) included with Thread Test Harness V1.1 R1.2.0 and R1.3.0.