How have they determind that VFR ACARS was disabled before the handover comms?
MH370 reached its cruising altitude FL350 at 17.03 UTC. At 17.07 UTC (01.07 local) the last RR (TOC) message was transmitted).
After that no RR ACARS messages was to be expected for a long time.
So how do they conclude 'disabled' and not just 'not transmitting'?
I would say the ACARS could have been disabled around the same time as the transponder - at 17.21 UTC.