We are testing copter 4.0.3 with IR-lock. From what we understand, it does detect and estimate the distance to the beacon, but it doesn’t seem to attempt to track it (or stabilize above it). Also, there is no indication in Mission Planner that it is actually switched to precision loiter. The switch on the remote is set to 39 for precision loiter (3-position switch with manual and position hold as the two other modes).
Any tips are more than welcome