PH2.1 and traditional heli

Few days back after a long wait I received my PH2 ( Pixhawk2). The first thing I did was remove the pixhawk from my 450 Traditional heli and install the pixhawk 2. Since I was already flying 3.4.6, I just copied the same tuning parameters and seems to be not too bad. However I visited the proficnc website and it says Arducpter 3.5.

  1. Does this mean that I should not be flying PH2 with 3.4.6 as the support is not complete and I may get a crash?
  2. The pixhawk 1 had much better Alt hold, PH2 seems to have a drift and needs occasional correction. Is anybody else seeing this issue as well?

I just went through setting up a Pixhawk 2.1 on a heli, admittedly my first go at it. Because of my infancy, i inadvertently uploaded 3.4.6 and had a host of issues I thought were hardware related that were “completely” solved by flashing 3.5 . Gyro drift, bad gyro health errors, accel calibration issues, bad ahrs errors etc.
3.5 has worked “on the bench” so far, as i have “not flown” this yet, but so far things in the gyro, mag and accel department look good after properly installing 3.5