I can't remember ever reading anything about this, but today I got a message (after updating the firmware two days ago) to update the BATTERIES, which I did. It takes about a minute or less for each one. Simple. Then I took my MM out for a fly and clipped some bushes in my barnyard and it immediately shut off and fell into the grass and I noticed the mishap took a small chip off one of the rear left blades, along with making a bit or roughness to the leading edge. So I thought that would be it until the new ordered propellers arrive, and after previous going through that well discussed issue of the warning that comes on the screen after downloading the latest firmware a couple of days ago. So just for the fun of it, I decided to try and fly it anyway in the large pasture behind my house and I put it through its paces hard in C,P, and Sport Modes to see if I could get the return to base/install new propellers warning to come up and I couldn't. It never flew better as I ran a full battery down. Go figure. It's a mystery to me but perhaps updating the batteries may have had something to do with it. I've got two set of props on the way, both standard issue and carbon. It will be fun to see how they compare.