Hello, I'm testing SD for android  version 3.16.3.21673 and I want to cycle between route waypoints while I'm flying, I mean. I have a route with waypoints A,B,C,D and E. I'm in the leg from A to B and I want to go to D. I know I can tap on the magnifier and search for D. That's ok but when I'm about to reach D, I want to go to B. If I tap on the magnifier, B isn't there.

That behaviour doesn't exist in SkyDemon. If you want to alter your planned route you can do so, by rubber-banding or by taking a shortcut or by routing directly to any waypoint. What you're describing - setting the next waypoint to something other than the waypoint at the end of the leg you're navigating - isn't possible in SkyDemon.

I see. Has anybody asked this before? I mean, VFR flying should be very flexible, cyrcling between your route waypoints should be something not very weird for a VFR pilot in fact, it can be done on other vfr moving map software. Think about it, just two buttons , Next/Prev.

It was asked for a few times in our early days, but that's ten years ago. It's just a matter of what you're used to. If you want to go flying without a particular plan, as it sounds in this case, you might be better off planning a "local route" in SkyDemon, where you just declare you'll be flying within X miles of your airfield. That gives you a NOTAM and weather brief appropriate to that area. In flight, you can always re-plan on the go with a couple of touches of the map, which will give you a route direct from your current position to any waypoint.