mavlink-devguide/kr/mavlink_2.md

MAVLink 2

MAVLink version 2 is a backward-compatible new version. The main new features are:

• Support for more than 256 message IDs (now 24 bit or over 16 million packets)
• Packet signing (authentication)
• Support for extending existing messages
• Support for variable length arrays

Upgrading an existing C installation

The existing v1 library can be simply upgraded by dropping in the v2 library from Github:

https://github.com/mavlink/c_library_v2

The v2 library will send packets in MAVLink v2 framing by default. In order to default to v1, run this code snippet on boot:

mavlink_status_t* chan_state = mavlink_get_channel_status(MAVLINK_COMM_0);
chan_state->flags |= MAVLINK_STATUS_FLAG_OUT_MAVLINK1;

It is advisable to switch to MAVLink v2 when the communication partner sends MAVLink v2 - the complete handshaking for versions is described in this guide. The minimal solution is to watch incoming packets using code similar to this:

if (mavlink_parse_char(MAVLINK_COMM_0, buf[i], &msg, &status)) {

	// check if we received version 2 and request a switch.
	if (!(mavlink_get_channel_status(MAVLINK_COMM_0)->flags & MAVLINK_STATUS_FLAG_IN_MAVLINK1)) {
		// this will only switch to proto version 2
		chan_state->flags &= ~(MAVLINK_STATUS_FLAG_OUT_MAVLINK1);
	}
}