Well ... as the starter of this thread ... I agree with all points. Brian & Bill are both right (though I use a flying club an hour away, so while I have used external power it's not that convenient). And if one has to choose one or the other, I get that. But ... I sell non-aviation products that utilize hardware & software (relatively small companies compared to industry giants), and they supply off-line versions and update them simultaneously with the hardware versions. They figured how to do that, so I thought so could Dynon. Hey if it can happen, great, if not, OK.