OpenTX 2.1.9, released in September 2016, is a significant stable version of the open-source firmware for RC radio transmitters. It is particularly notable as the last version to support AVR-based radios like the Turnigy 9X and 9XR. Download Links
Downloading and Installing OpenTX 2.1.9
pfeerick commented. pfeerick. on Dec 20, 2023. Contributor. Looks like the link is wrong on the website. The proper link is https: OpenTX 2.1 released! - Page 6 - openrcforums opentx 2.1.9 download
Download OpenTX Companion: Visit the official OpenTX 2.1.9 release page to find the installation files for Windows, macOS, or Linux. OpenTX 2
Once you have OpenTX Companion 2.1 installed and your radio connected via USB: released in September 2016