In the v01.00.0400 release notes is the following line :

  Adjusted flight altitude and distance in payload mode.

I've been unable to find any info about what this means precisely.  Does anyone have a lead?

Thanks.

It just means if your flying with prop guards on you can fly at slightly higher altitude  and more distance

Hello and good day JeffC68. Thank you for reaching out and for the inquiry. This feature optimizes and improves the flight altitude and the distance when using the propeller guard of the DJI Mavic Mini and when the payload mode function in the DJI Fly application. Thank you.

I'm sure it limits the MM to the same as having prop guards fitted.

To ensure flight safety, after attaching the 360° Propeller Guard, the maximum speed is limited to 8 m/s, the flight altitude is limited to 120 meters, and the flight distance is limited to 100 meters.

W̶h̶e̶r̶e̶ ̶d̶i̶d̶ ̶y̶o̶u̶ ̶f̶i̶n̶d̶ ̶t̶h̶e̶ ̶r̶e̶l̶e̶a̶s̶e̶ ̶n̶o̶t̶e̶s̶ ̶f̶o̶r̶ ̶v̶0̶1̶.̶0̶0̶.̶0̶4̶0̶0̶?̶ nevermind I forgot v01.00.0400? came out in 2019