QGC MAVLink Version Decision

Hello together,

I noticed that QGC switches from MAVLink 2 to MAVLink 1 as soon as certain requests are not answered as expected. It is enough if the COMMAND_ACK from FC contains a 3 as result. The 3 stands for “Command or mission item is not supported, other commands would be accepted.”.

Older PX4 firmware versions do not know the message MAV_CMD_REQUEST_MESSAGE for example. As soon as QGC (Windows v4.20) asks for the AUTOPILOT_VERSION with this message, the FC answers that it does not know the version (COMMAND ACK with result == 3). QGC then switches to MAVLink 1.

Is the problem known? Is there a way to force QGC to stay with MAVLink 2?

Updating the firmware from the FC is not an option in our case. Mavlink 1 is not supported by the device either.