Using MAVlink v1.0 or v.2.0?

ArduCopter Copter 3.5
1

I wasn’t able to understand if from copter 3.5 the MAVlink protocol is v1.0 or v2.0 or if I can choose it.
Any help?

PS: also mission planner supports MAVLink v1.0 and v2.0 or only v1.0?