Hi - I've been flying on 3.7.1 for a few weeks and all's been ok apart from FlightDeck would not work so just used an old 3dr 433MHz radio pair to view telemetry.
Updated to 3.8 last week and everything is working great, including FlightDeck.
That was on a Pixhawk 1 - I have been having issues with all my Pixhawk 2.1s where I warm up in the car and then carry it to the take-off area. By the time I get there, the gyros are inconsistent and will not allow me to arm. The easiest way to find this out is listen to the audio on Mission Planner. It was driving me mad because no output on the Flight Screen - turn on audio and it's literally shouting at me. Just a power cycle fixes the problem.
I'm not keen on power cycles with companion computers because they prefer a shutdown and that takes time.
Hope that helps.