We are compliant with LoRaWAN specifications, as we have certified our modules, and FSK mode is optional.
Just fyi, the SX drivers are here: https://github.com/pycom/pycom-micropython-sigfox/tree/master/drivers/sx127x/sx1272
@catalin Where do you see in the Lora Alliance specification DR7 is optional in EU868? BTW, is DR6 implemented? Well, certification means you passed the test but doesn't guarantee full compatibility. Also, on the competitive side you are missing a feature supported by nearly all others.