The only fully-functional stack currently available requires Python >= 3.8, which is the main limitation to where it will run. But there’s still a lot you can do with that!
there is a pretty compatible rust implementation as well which claims to target microcontrollers https://github.com/BeechatNetworkSystemsLtd/Reticulum-rs
there is a pretty compatible rust implementation as well which claims to target microcontrollers https://github.com/BeechatNetworkSystemsLtd/Reticulum-rs