have been using active track quite abit and it has been great.
was just wondering why the lastest update to this caps the speed at 15km/h now the mavic hardley keeps up with anything

Same here. Used to work 100% fine in all modes, now I can't even find the buttons to chose between Spotlight, Trace and Profile in the GO4 app anymore. It's a lot less intuitive, and practically useless. Can't keep up with even slow rowing boats, the AC seem to just stay there hovering in a fixed position.

what device are you using? 4.0.5 on android increased the active track to 15m/s = 54km/h

Also... while testing with 4.0.3, i had the mavic going about 18m/s while tracking a car... was kind of unexpected...