M950 K parameter

[punktphil]

Hey, I just set up my printer to work as a small CNC for PCB milling.
But the M950 command gives me trouble. I'm using a BLDC motor with ESC (PWM Servo control).
50Hz PWM, 1..2ms pulse width
Board: Duet 3 Mini 5+
config:

M950 R0 C"io3.out" L0:10000 Q50 K0.05:0.1

I can set the spindle speed with M3 SXXXX, but it still outputs 0..100% PWM.
from https://docs.duet3d.com/en/User_manual/Reference/Gcodes:
Kaaa(:bbb[:ccc]) (optional, for spindles only, RRF 3.5 and later) Optional PWM values (0..1) for spindle control (max [aaa] - or - min, max [aaa:bbb] - or - min, max, idle [aaa:bbb:ccc])
Also, the latest RRF is 3.4.1 (which I'm running). Typo?
Did somebody get the K parameter to work?

[jay_s_uk]

@punktphil looks like that's being introduced in 3.5. You'll find that as features get added to the firmware (at pre beta and beta stages), they'll get documented as it's easier to create the docs when you add features rather than remember to go back and do it.
So for the time being, you can't use K