ARDUSUB and Manual_Slew_rate

Hi All,
is it not probably the best place where to write as Ardusub is not mentioned on any categories but as it is a subsystem of ardupilot i hope anybody can clarify the issue.

On the ardusub version 3.5.4, there’s a parameters called MANUAL_SLEW_RATE , this allow to regulate the how smooth thrusters movement should be when going to 0 up to 100% and viceversa.

Seems that from the version 4.0, this parameters has been hide or not anymore used. Do you know the reason? OR anybody could have a solution on how to re-enable this value again on the latest ardusub version?

Cheers